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British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Feather pecking and cannibalism in a caged layer flock a
Jean Allen & G. C. Perry
a
a
Department of Animal Husbandry, University of Bristol, Lang ford House, Langford, Bristol, BS18 7DU, England Published online: 08 Nov 2007.
To cite this article: Jean Allen & G. C. Perry (1975) Feather pecking and cannibalism in a caged layer flock, British Poultry Science, 16:5, 441-451 To link to this article: http://dx.doi.org/10.1080/00071667508416212
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Br. Poult. Sci., 16: 441-451. 1975
FEATHER
Longman: printed in Great Britain
PECKING AND CANNIBALISM CAGED LAYER FLOCK
IN A
JEAN ALLEN AND G. C. PERRY Department of Animal Husbandry, University of Bristol, Lang ford House, Langford, Bristol BS18 7DU, England
Downloaded by [University of Glasgow] at 12:57 19 September 2013
Received for publication 19th August 1974
1. The progress of feather pecking and cannibalism was recorded from hatching to end of lay in a flock of caged layers and the influence of group size, floor area allowance and cage tier upon the incidence of these activities during lay assessed. 2. The largest group suffered more cannibalism and feather pecking than smaller groups, floor area allowance and tier being less important factors. 3. A significant trend was found for one death from cannibalism to be followed by more in the same cage. 4. It was concluded that feather pecking and cannibalism are separate phenomena, although the same cage conditions increased the incidence of both. 5. Cannibalism may be divided into vent pecking and cannibalism affecting other parts of the body, the former is independent of feather pecking and the latter, though usually preceded by feather pecking, is only indirectly associated with it. INTRODUCTION
The aetiology of feather pecking and cannibalism amongst domestic fowl and game birds is not fully understood, although many possible causative factors have been investigated and preventive measures suggested. Kull (1948) found that feather eating and cannibalism could be prevented with dietary supplements of manganese sulphate and horn meal while Neal (1956) used methionine to curb cannibalism in a laying flock. Madsen (1966), however, failed to reduce feather pecking in pheasants with supplements of arginine, and Hughes and Duncan (1972) found diet to have only a minor influence on the incidence of these aberrant behaviour patterns in chickens. The form in which food is given may also affect the occurrence of cannibalism in individual flocks. Ziegenhagen et al. (1947) and Bearse et al. (1949) compared pelleted or crumbed diets with food in mash form, and found less cannibalism in mash-fed birds. Richter (1954) concluded that feather eating was an " hereditary fault", and 441
Downloaded by [University of Glasgow] at 12:57 19 September 2013
442
JEAN ALLEN AND G. G. PERRY
Hughes and Duncan (1972), in a multifactorial study, found significant differences between strains of birds. Hughes (1973) using the same strains also found that they differed, but the order of severity of pecking damage was reversed. In addition, environmental factors such as light intensity, ventilation and type of housing (Kull, 1948) have been implicated as possible causes, and Hughes (1973) was able to influence feather pecking with implanted gonadal hormones. An experiment to study the effects of group size and floor space allowance on battery egg production was in progress when feather pecking and then cannibalism broke out amongst the chicks in some cages before 2 weeks of age. Attempts to prevent further outbreaks by reducing light intensity and treating injured birds were not successful and debeaking was prohibited by the requirements of the original experiment. It was decided to proceed with the experiment as planned, and keep a record of all deaths and their causes and to follow the progress of feather pecking and cannibalism through the laying period. The term cannibalism is used to denote damage inflicted upon a bird by its cage mates sufficiently severe to cause its death. MATERIALS AND METHODS
Babcock B300 chicks, a light hybrid strain derived from the White Leghorn, were used. A total of 3879 female chicks were allocated to cages in a controlled environment battery house. Fifty-four birds were placed in each top-tier cage. Six nipple drinkers were equally spaced along the centre of each cage and continuous food troughs were situated on either side. At 7 weeks, half the birds were moved to similar middle-tier cages. At 18 weeks all cages were converted to accommodate the point-of-lay pullets and the bottom tier was brought into use. The pullets, 2160 birds in number, were caged in groups of 3, 4 or 6 with a floor area allowance of 658-1 or 438-7 cm2 per bird. The group size and floor area treatments were repeated on each tier. The rearing cages were partitioned along the long axis so that the nipple drinkers were sited at the rear of each laying cage and the food trough was at the front. Cage depth was constant at 43 cm, the cage width being altered to provide the required floor area. Cage dimensions and the codes by which the different cage conditions are identified are shown in Table 1. Each of the 18 cage conditions (3 group sizes x 2 floor space allowances x 3 tiers) was represented by 12 birds per replicate and 10 replicates were used. Commercial diets were used throughout the experiment: details of the feeding programme are shown in Table 2. Food and water were available ad libitum. Artificial light was provided for 24 h during the first 2 d, then gradually reduced to 11 h for the rest of the rearing period. The photoperiod was increased by 30 min per week from the 16th week to a final length of 16 h. This was maintained until the end of lay. The house was pre-heated to 34*5 °C to receive the i-d-old chicks. The temperature was reduced every 3 or 4 d to give a reduction equivalent to 0-5 °C for every day of age, until a temperature of 21 °C was achieved. Artificial ventilation was provided from 7 weeks. The thermostatically controlled fans and heater maintained the temperature between 20 and 22 °C during the remainder of the
FEATHER PECKING AND CANNIBALISM
443
rearing period and throughout most of lay, but during the second, third and fourth laying months, outside temperature was very high, and house temperatures of up to 31 °C were recorded in mid-afternoon. TABLE 1 Laying cage codes and dimensions
ode
Downloaded by [University of Glasgow] at 12:57 19 September 2013
A B C D E F
Group size 3 4 6 3 4 6
Floor area per bird (cm8) 658 658 658 439 439 439
Cage width (cm) 45-6 6o-8 91-2 30-6 40-8 61-2
Trough length per bird (cm) 15-2 15-2 15-2
Cages per tier in one replicate
IO-2 10-2 10-2
4 3
4 3 2
2
TABLE 2 Feeding programme
Age (weeks)
Food starter crumbs rearer mash grower mash mash
Protein (%)
ACS
+ + — 18 + — Dead birds were removed daily and their cages recorded. All birds, except those which had obviously been killed by severe cannibalism, were examined post mortem at the M.A.F.F. Veterinary Investigation Centre at Langford. Feather pecking was first noticed at 10 d of age when chicks with bloodied skin on the wings and back were found. By 17 d damaged birds were observed in many cages and an examination of all birds took place. At this time presence or absence of pecking damage was noted for right and left wings, back and tail of each bird. During the laying period a scoring system based upon that devised by Hughes and Duncan (1972) was used to estimate the severity of feather pecking. Pecking was rated by visual estimation on the following five point scale: Score Description 0 No denuded areas of skin 1 Denuded area less than 2 x 2 cm 2 Denuded area up to 5 x 5 cm 3 Denuded area greater than 5 x 5 cm 4 Denuded area with skin haemorrhage All birds were handled for a reliable assessment, and ventral and dorsal surfaces, tail and wings were scored separately for each bird, giving a maximum possible score of 16 points. Two complete replicates, totalling 432 birds, were examined at 18, 23, 31, 51 and 67 weeks of age. The same birds were examined on each occasion where possible, but if mortality had reduced the original number of birds, a complete cage of the same condition was substituted. By the last examination no complete F cages remained on the middle tier and five cages with five birds were used. A three-factor (group size x floor space allowance x tier) analysis of variance was performed on each set of data and a multiple range test (Duncan, 1955) was used to detect significant differences between means. 0-6 6-11 11-18
Chick Pullet Pullet Layer
18-5 16-5 14-0 17-0
JEAN ALLEN AND G. C. PERRY
444 RESULTS Cannibalism during rearing
The first death from cannibalism was recorded at 2 weeks of age. Chicks with skin damage from feather pecking were treated with Stockholm tar and the light
Downloaded by [University of Glasgow] at 12:57 19 September 2013
.100'
80Key All other causes Cannibalism
«
60-
40-
20-
1 4 6 8 10 12 14 16 18 Two-week periods (age in weeks at end of period)
F:G. 1.—Mortality during rearing.
intensity reduced. Light distribution in the house was poor and illumination at the cage front varied between 6-99 lx (top cages opposite lights) and o-86 lx (bottom cages between lights) at the reduced level. The incidence of cannibalism gradually decreased as the rearing period progressed (see Fig. 1) but by 18 weeks 3 7 % of the
FEATHER PECKING AND CANNIBALISM
445
flock had been killed. Of the 142 cannibalised birds, 19 had been pecked around the cloaca and partially eviscerated, but the remainder died from haemorrhage of wounds on other parts of the body, frequently the dorsal surface or base of the tail. These wounds appeared to have been associated with localised feather pecking and the rest of the body was usually well feathered. Feather pecking during rearing
Feather pecking, which was first observed at 10 d of age, was established in 27 of the 71 rearing cages by 17 d. The number of birds affected in each cage ranged from 1 to 34 (see Table 3). Tail pecking was rare at this stage and the back and TABLE 3
Downloaded by [University of Glasgow] at 12:57 19 September 2013
Incidence of feather pecking in ij-day-old chicks
Cage i6)» i7) J9* 23* 25)
10
27) 30
34)* 35) 37* 45 48
5°) 50
52)*
53) 54) 59 62 64) 65)
0 0 0
21 11
5 "3 14 30 14 18
70)
Total
11
4 8 9 0 1
9 5
5
2
11
7
9
1
7
5 3 18
3 9 10
69)*
4 9
10
1
67)
7
1
3 23
66)*
Wing damage
3 4 5
26)*
70
No. injured
13 34 3 290
0 1
4 3 8 3 1
123
Back damage t 1 0 1 1
Wing and back
Tail 2 0 2 0 1 3 0 0 0
o
3
9°
o o o 0 29 8 6 3 1 1 7 t o 0 1 2 3 7 4 27 2 109
0 0 0 5 0 5 0 o 5 0 0 2 0 2 0 o o 1 0 0 0 5 0 0 0 2 0 0 0 1 0 4 0 0 0 1 1
1 3
3 1
0 0
57
* Cages opposite lights.
Adjacent cages.
wings were the most commonly pecked areas. Some cages seemed to prefer a particular area of the body. In cage 37, for example, all 30 injured birds had been pecked on the back, whilst only one had suffered damage to a wing. In cage 62 only 5 of the 23 pecked chicks had been attacked on the back but wing damage was common. It is interesting to note that cages where feather pecking occurred tended to be grouped together. These groups were distributed throughout the house and had no common factor such as proximity to doors or walls. The house lights were positioned approximately four rearing cage lengths apart, so there was a range of
446
JEAN ALLEN AND G. C. PERRY
light intensity within each feather pecked group. However, the most brightly lit cages tended to be at the centre of the group. Three of the single feather damaged cages were directly opposite a light and the rest were very close. It seems possible that feather pecking originated in the brightly lit cages and then spread to those adjacent. The spread continued and all cages were affected shortly after the 17-d survey. Injured birds continued to be treated with Stockholm tar. As juvenile plumage replaced the chicks' down, tail feathers were pulled more often and the injuries on wings and back decreased. As the flock matured, the incidence of feather pecking decreased and most birds were fully feathered at point-of-lay. 8O-1
Downloaded by [University of Glasgow] at 12:57 19 September 2013
Key All other causes Cannibalism
60-
.£>
40-
20-
1
2
3
4
5
6
7
8
9
10
11
12
13
Laying months FIG. 2.—Mortality during lay.
Cannibalism during lay
The laying period was divided into 13 4-week laying " months ". Mortality through the laying year is shown in Fig. 2 and deaths from cannibalism for each group are shown in Table 4. Throughout the laying period 546 deaths (25-3% of the point-of-lay flock) were recorded, of which 228 (41-8% of total deaths) were due
FEATHER PECKING AND CANNIBALISM
447 to cannibalism. It can be seen that more than half of the cannibalism deaths occurred in the first 4 months of lay. TABLE 4 Cannibalism during lay
Floor area per bird
w 658
Downloaded by [University of Glasgow] at 12:57 19 September 2013
658
Group size 3
4
Code A
13-month total
4-month total
Top
10
Middle Bottom Total
12
7 5 3 15 8 9 3
Tier
B
4 26
Top
15 14 5 34
20
Middle Bottom Total
31 14 17 62
17 7 '3 37
Top
19
10
Middle Bottom Total
11
5
Middle Bottom Total 658
439
439
439
6
3
4
6
G
Top
D
E
7
2
17
Middle Bottom Total
37 8 7 3 18
Top
20
iG
24 7 51 228
13 3 32 132
Top
F
Middle Bottom Total Overall total
5 6 0 11
An analysis of variance was performed on the total deaths from cannibalism. Groups of six birds and top-tier cages tended to suffer a higher rate of mortality but interaction effects were high and the differences between these and the other cage conditions were not significant. However, when the data of the first 4 months alone were analysed, significant differences between group sizes were found, with cannibalism occurring more frequently in the groups of 6 birds (11*50 deaths) than in groups of 3 or 4 (5€33 and 5*17 deaths, respectively: P
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Feather pecking and cannibalism in a caged layer flock a
Jean Allen & G. C. Perry
a
a
Department of Animal Husbandry, University of Bristol, Lang ford House, Langford, Bristol, BS18 7DU, England Published online: 08 Nov 2007.
To cite this article: Jean Allen & G. C. Perry (1975) Feather pecking and cannibalism in a caged layer flock, British Poultry Science, 16:5, 441-451 To link to this article: http://dx.doi.org/10.1080/00071667508416212
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Br. Poult. Sci., 16: 441-451. 1975
FEATHER
Longman: printed in Great Britain
PECKING AND CANNIBALISM CAGED LAYER FLOCK
IN A
JEAN ALLEN AND G. C. PERRY Department of Animal Husbandry, University of Bristol, Lang ford House, Langford, Bristol BS18 7DU, England
Downloaded by [University of Glasgow] at 12:57 19 September 2013
Received for publication 19th August 1974
1. The progress of feather pecking and cannibalism was recorded from hatching to end of lay in a flock of caged layers and the influence of group size, floor area allowance and cage tier upon the incidence of these activities during lay assessed. 2. The largest group suffered more cannibalism and feather pecking than smaller groups, floor area allowance and tier being less important factors. 3. A significant trend was found for one death from cannibalism to be followed by more in the same cage. 4. It was concluded that feather pecking and cannibalism are separate phenomena, although the same cage conditions increased the incidence of both. 5. Cannibalism may be divided into vent pecking and cannibalism affecting other parts of the body, the former is independent of feather pecking and the latter, though usually preceded by feather pecking, is only indirectly associated with it. INTRODUCTION
The aetiology of feather pecking and cannibalism amongst domestic fowl and game birds is not fully understood, although many possible causative factors have been investigated and preventive measures suggested. Kull (1948) found that feather eating and cannibalism could be prevented with dietary supplements of manganese sulphate and horn meal while Neal (1956) used methionine to curb cannibalism in a laying flock. Madsen (1966), however, failed to reduce feather pecking in pheasants with supplements of arginine, and Hughes and Duncan (1972) found diet to have only a minor influence on the incidence of these aberrant behaviour patterns in chickens. The form in which food is given may also affect the occurrence of cannibalism in individual flocks. Ziegenhagen et al. (1947) and Bearse et al. (1949) compared pelleted or crumbed diets with food in mash form, and found less cannibalism in mash-fed birds. Richter (1954) concluded that feather eating was an " hereditary fault", and 441
Downloaded by [University of Glasgow] at 12:57 19 September 2013
442
JEAN ALLEN AND G. G. PERRY
Hughes and Duncan (1972), in a multifactorial study, found significant differences between strains of birds. Hughes (1973) using the same strains also found that they differed, but the order of severity of pecking damage was reversed. In addition, environmental factors such as light intensity, ventilation and type of housing (Kull, 1948) have been implicated as possible causes, and Hughes (1973) was able to influence feather pecking with implanted gonadal hormones. An experiment to study the effects of group size and floor space allowance on battery egg production was in progress when feather pecking and then cannibalism broke out amongst the chicks in some cages before 2 weeks of age. Attempts to prevent further outbreaks by reducing light intensity and treating injured birds were not successful and debeaking was prohibited by the requirements of the original experiment. It was decided to proceed with the experiment as planned, and keep a record of all deaths and their causes and to follow the progress of feather pecking and cannibalism through the laying period. The term cannibalism is used to denote damage inflicted upon a bird by its cage mates sufficiently severe to cause its death. MATERIALS AND METHODS
Babcock B300 chicks, a light hybrid strain derived from the White Leghorn, were used. A total of 3879 female chicks were allocated to cages in a controlled environment battery house. Fifty-four birds were placed in each top-tier cage. Six nipple drinkers were equally spaced along the centre of each cage and continuous food troughs were situated on either side. At 7 weeks, half the birds were moved to similar middle-tier cages. At 18 weeks all cages were converted to accommodate the point-of-lay pullets and the bottom tier was brought into use. The pullets, 2160 birds in number, were caged in groups of 3, 4 or 6 with a floor area allowance of 658-1 or 438-7 cm2 per bird. The group size and floor area treatments were repeated on each tier. The rearing cages were partitioned along the long axis so that the nipple drinkers were sited at the rear of each laying cage and the food trough was at the front. Cage depth was constant at 43 cm, the cage width being altered to provide the required floor area. Cage dimensions and the codes by which the different cage conditions are identified are shown in Table 1. Each of the 18 cage conditions (3 group sizes x 2 floor space allowances x 3 tiers) was represented by 12 birds per replicate and 10 replicates were used. Commercial diets were used throughout the experiment: details of the feeding programme are shown in Table 2. Food and water were available ad libitum. Artificial light was provided for 24 h during the first 2 d, then gradually reduced to 11 h for the rest of the rearing period. The photoperiod was increased by 30 min per week from the 16th week to a final length of 16 h. This was maintained until the end of lay. The house was pre-heated to 34*5 °C to receive the i-d-old chicks. The temperature was reduced every 3 or 4 d to give a reduction equivalent to 0-5 °C for every day of age, until a temperature of 21 °C was achieved. Artificial ventilation was provided from 7 weeks. The thermostatically controlled fans and heater maintained the temperature between 20 and 22 °C during the remainder of the
FEATHER PECKING AND CANNIBALISM
443
rearing period and throughout most of lay, but during the second, third and fourth laying months, outside temperature was very high, and house temperatures of up to 31 °C were recorded in mid-afternoon. TABLE 1 Laying cage codes and dimensions
ode
Downloaded by [University of Glasgow] at 12:57 19 September 2013
A B C D E F
Group size 3 4 6 3 4 6
Floor area per bird (cm8) 658 658 658 439 439 439
Cage width (cm) 45-6 6o-8 91-2 30-6 40-8 61-2
Trough length per bird (cm) 15-2 15-2 15-2
Cages per tier in one replicate
IO-2 10-2 10-2
4 3
4 3 2
2
TABLE 2 Feeding programme
Age (weeks)
Food starter crumbs rearer mash grower mash mash
Protein (%)
ACS
+ + — 18 + — Dead birds were removed daily and their cages recorded. All birds, except those which had obviously been killed by severe cannibalism, were examined post mortem at the M.A.F.F. Veterinary Investigation Centre at Langford. Feather pecking was first noticed at 10 d of age when chicks with bloodied skin on the wings and back were found. By 17 d damaged birds were observed in many cages and an examination of all birds took place. At this time presence or absence of pecking damage was noted for right and left wings, back and tail of each bird. During the laying period a scoring system based upon that devised by Hughes and Duncan (1972) was used to estimate the severity of feather pecking. Pecking was rated by visual estimation on the following five point scale: Score Description 0 No denuded areas of skin 1 Denuded area less than 2 x 2 cm 2 Denuded area up to 5 x 5 cm 3 Denuded area greater than 5 x 5 cm 4 Denuded area with skin haemorrhage All birds were handled for a reliable assessment, and ventral and dorsal surfaces, tail and wings were scored separately for each bird, giving a maximum possible score of 16 points. Two complete replicates, totalling 432 birds, were examined at 18, 23, 31, 51 and 67 weeks of age. The same birds were examined on each occasion where possible, but if mortality had reduced the original number of birds, a complete cage of the same condition was substituted. By the last examination no complete F cages remained on the middle tier and five cages with five birds were used. A three-factor (group size x floor space allowance x tier) analysis of variance was performed on each set of data and a multiple range test (Duncan, 1955) was used to detect significant differences between means. 0-6 6-11 11-18
Chick Pullet Pullet Layer
18-5 16-5 14-0 17-0
JEAN ALLEN AND G. C. PERRY
444 RESULTS Cannibalism during rearing
The first death from cannibalism was recorded at 2 weeks of age. Chicks with skin damage from feather pecking were treated with Stockholm tar and the light
Downloaded by [University of Glasgow] at 12:57 19 September 2013
.100'
80Key All other causes Cannibalism
«
60-
40-
20-
1 4 6 8 10 12 14 16 18 Two-week periods (age in weeks at end of period)
F:G. 1.—Mortality during rearing.
intensity reduced. Light distribution in the house was poor and illumination at the cage front varied between 6-99 lx (top cages opposite lights) and o-86 lx (bottom cages between lights) at the reduced level. The incidence of cannibalism gradually decreased as the rearing period progressed (see Fig. 1) but by 18 weeks 3 7 % of the
FEATHER PECKING AND CANNIBALISM
445
flock had been killed. Of the 142 cannibalised birds, 19 had been pecked around the cloaca and partially eviscerated, but the remainder died from haemorrhage of wounds on other parts of the body, frequently the dorsal surface or base of the tail. These wounds appeared to have been associated with localised feather pecking and the rest of the body was usually well feathered. Feather pecking during rearing
Feather pecking, which was first observed at 10 d of age, was established in 27 of the 71 rearing cages by 17 d. The number of birds affected in each cage ranged from 1 to 34 (see Table 3). Tail pecking was rare at this stage and the back and TABLE 3
Downloaded by [University of Glasgow] at 12:57 19 September 2013
Incidence of feather pecking in ij-day-old chicks
Cage i6)» i7) J9* 23* 25)
10
27) 30
34)* 35) 37* 45 48
5°) 50
52)*
53) 54) 59 62 64) 65)
0 0 0
21 11
5 "3 14 30 14 18
70)
Total
11
4 8 9 0 1
9 5
5
2
11
7
9
1
7
5 3 18
3 9 10
69)*
4 9
10
1
67)
7
1
3 23
66)*
Wing damage
3 4 5
26)*
70
No. injured
13 34 3 290
0 1
4 3 8 3 1
123
Back damage t 1 0 1 1
Wing and back
Tail 2 0 2 0 1 3 0 0 0
o
3
9°
o o o 0 29 8 6 3 1 1 7 t o 0 1 2 3 7 4 27 2 109
0 0 0 5 0 5 0 o 5 0 0 2 0 2 0 o o 1 0 0 0 5 0 0 0 2 0 0 0 1 0 4 0 0 0 1 1
1 3
3 1
0 0
57
* Cages opposite lights.
Adjacent cages.
wings were the most commonly pecked areas. Some cages seemed to prefer a particular area of the body. In cage 37, for example, all 30 injured birds had been pecked on the back, whilst only one had suffered damage to a wing. In cage 62 only 5 of the 23 pecked chicks had been attacked on the back but wing damage was common. It is interesting to note that cages where feather pecking occurred tended to be grouped together. These groups were distributed throughout the house and had no common factor such as proximity to doors or walls. The house lights were positioned approximately four rearing cage lengths apart, so there was a range of
446
JEAN ALLEN AND G. C. PERRY
light intensity within each feather pecked group. However, the most brightly lit cages tended to be at the centre of the group. Three of the single feather damaged cages were directly opposite a light and the rest were very close. It seems possible that feather pecking originated in the brightly lit cages and then spread to those adjacent. The spread continued and all cages were affected shortly after the 17-d survey. Injured birds continued to be treated with Stockholm tar. As juvenile plumage replaced the chicks' down, tail feathers were pulled more often and the injuries on wings and back decreased. As the flock matured, the incidence of feather pecking decreased and most birds were fully feathered at point-of-lay. 8O-1
Downloaded by [University of Glasgow] at 12:57 19 September 2013
Key All other causes Cannibalism
60-
.£>
40-
20-
1
2
3
4
5
6
7
8
9
10
11
12
13
Laying months FIG. 2.—Mortality during lay.
Cannibalism during lay
The laying period was divided into 13 4-week laying " months ". Mortality through the laying year is shown in Fig. 2 and deaths from cannibalism for each group are shown in Table 4. Throughout the laying period 546 deaths (25-3% of the point-of-lay flock) were recorded, of which 228 (41-8% of total deaths) were due
FEATHER PECKING AND CANNIBALISM
447 to cannibalism. It can be seen that more than half of the cannibalism deaths occurred in the first 4 months of lay. TABLE 4 Cannibalism during lay
Floor area per bird
w 658
Downloaded by [University of Glasgow] at 12:57 19 September 2013
658
Group size 3
4
Code A
13-month total
4-month total
Top
10
Middle Bottom Total
12
7 5 3 15 8 9 3
Tier
B
4 26
Top
15 14 5 34
20
Middle Bottom Total
31 14 17 62
17 7 '3 37
Top
19
10
Middle Bottom Total
11
5
Middle Bottom Total 658
439
439
439
6
3
4
6
G
Top
D
E
7
2
17
Middle Bottom Total
37 8 7 3 18
Top
20
iG
24 7 51 228
13 3 32 132
Top
F
Middle Bottom Total Overall total
5 6 0 11
An analysis of variance was performed on the total deaths from cannibalism. Groups of six birds and top-tier cages tended to suffer a higher rate of mortality but interaction effects were high and the differences between these and the other cage conditions were not significant. However, when the data of the first 4 months alone were analysed, significant differences between group sizes were found, with cannibalism occurring more frequently in the groups of 6 birds (11*50 deaths) than in groups of 3 or 4 (5€33 and 5*17 deaths, respectively: P
