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British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Assessment of the effects of separate sex feeding on the welfare and productivity of broiler breeder females P. M. Hocking
a
a
Agricultural and Food Research Council , Institute for Grassland and Animal Production, Poultry Department , Roslin, Midlothian, EH25 9PS, Scotland Published online: 08 Nov 2007.
To cite this article: P. M. Hocking (1990) Assessment of the effects of separate sex feeding on the welfare and productivity of broiler breeder females, British Poultry Science, 31:3, 457-463, DOI: 10.1080/00071669008417278 To link to this article: http://dx.doi.org/10.1080/00071669008417278
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
British Poultry Science (1990) 31: 457-463
ASSESSMENT OF THE EFFECTS OF SEPARATE SEX FEEDING ON THE WELFARE AND PRODUCTIVITY OF BROILER BREEDER FEMALES
Downloaded by [University of Illinois at Urbana-Champaign] at 00:56 16 March 2015
P. M. HOCKING Agricultural and Food Research Council Institute for Grassland and Animal Production, Poultry Department, Roslin, Midlothian EH25 9PS, Scotland Received for publication 28th September 1989
Abstract 1. The welfare and productivity of female broiler breeders were studied in pens containing 15 females and 1 male where the sexes were fed together or separately by means of a grid with 40 mm spaces over the female feeders. 2. Average head width did not increase after 25 weeks of age. 3. The rate of lay was lower in separate compared with mixed -sex-fed pens but egg weight was similar. 4. The incidence of swollen heads and beak lesions was higher and feather loss and rate of food intake was lower in separate compared with mixed-sex-fed pens. 5. It was concluded that the grid spaces should be 42 mm wide to avoid adverse effects on welfare and productivity.
INTRODUCTION
Fitting simple barriers to the feeding trough to exclude the males which have larger heads has made it possible to feed male and female broiler breeders different diets and quantities. The size of the gap through which the females feed is clearly of crucial importance. If it is too large, separate feeding of the sexes will not be achieved. If it is too small they will not be able to feed and productivity and well-being of the flock will deteriorate. As part of an experiment to compare the effect of different male diets and target body weights on fertility, groups of birds were fed in pens with or without gridded troughs. At the time this experiment was conducted, a gap size of 40 mm was recommended by the two major breeding companies in the United Kingdom. Several attempts to introduce separate sex feeding in the field were apparently unsuccessful (Laughlin, 1988). The purpose of this paper is to assess objectively the effect of these grids on rate of lay and several aspect of the welfare of the females and to make recommendations for the future. A full account of results in the males is given by Hocking (1990). 457
458
P. M. HOCKING
Downloaded by [University of Illinois at Urbana-Champaign] at 00:56 16 March 2015
MATERIALS AND METHODS
At 20 weeks of age, 6 rooms each containing 12 pens 3-6 m2 littered with wood shavings and containing 15 female and 1 male broiler breeders (Cobb 500, The Cobb Breeding Co. Ltd, Chelmsford) were established. Feeding and lighting followed the breeders' recommended schedules. The females were fed a conventional diet containing 11-5 MJ metabolisable energy/kg, 160 g crude protein (CP)/kg and 34 g Ca/kg. During lay, they were allocated a maximum of 160 g/bird d decreasing by 1 g/bird d, weekly after 36 weeks of age. Water was available ad libitum from three nipple drinkers. Food was supplied in a trough 1830 mm longX 100 mm wide X 100 mm deep, the edge of which was 280 mm from the floor. In two pens in each room males and females fed from the same open trough. Food troughs in the remaining pens were fitted with an L-shaped grid so that the birds were presented with a series of 40 mm gaps through which the females only could feed. The males in these pens were fed in tube feeders suspended too high for the females to reach. Males in two of these pens in each room were fed a low protein (110 CP/kg) diet ad libitum. Males in the other pens were fed 4 allocations of the two diets (160 and 110 CP/kg) which resulted in average body weights at 60 weeks of age of 3-1, 3-5, 3*7 and 3-9 kg. Body weight for males fed the low protein diet ad libitum was 5-0 and for the mixed-sex-fed males 5*5 kg. Eggs were collected daily from 24 to 60 weeks of age. Settable eggs from each pen were weighed in bulk on one day each week. Body weight was recorded for all females at 20, 26, 32, 46 and 60 weeks of age. At the same ages, the head width of a sample of three females in each pen was determined by one person using a pair of calipers at the posterior point of the lower mandible. The birds selected were the first to weigh within 100 g of the anticipated flock mean and the first to weigh more than, or less than, two standard deviations from the mean. In this way, the head widths of three groups of hens of different body weights (small, medium and large) were obtained at each age. Concern that lighter, more active, males may over-mate (Dudgeon, 1986) was assessed by comparing the condition of females in representative treatments. At 60 weeks of age the females in pens with the heavier separate-fed males (treatment 4, Hocking, 1990) and in the mixed-fed pens (one pen from each room) were scored for the loss of feathers caused by treading during mating. Each bird was scored as follows: no damage to or loss of feathers (5); damage to or loss of feathers on not more than half of the back (4); no feathers over most of the back extending to the top of the thighs (3); bare skin over the back and thorax (2); back, thorax and thighs denuded (1). Necrotic lesions and erosion of the nares, mandible and maxilla were scored, separately, on all females at 60 weeks of age. The rate of food consumption by females in pens with and without a grid was determined at 60 weeks of age after the males had been removed. One pen of each type was selected at random in each room. The troughs were weighed before feeding (138 g/bird) and again 1, 3, 7 and 24 h afterwards. Data for food intake, body weights, head width and egg weight were
SEPARATE SEX FEEDING
459
TABLE 1
Body weight and head width of broiler breeder females and regression coefficients for head size on body weight
Category1
Downloaded by [University of Illinois at Urbana-Champaign] at 00:56 16 March 2015
Body weight (kg) Small Medium Large All females
Age (weeks)
SED
20
25
32
45
60
1-63 1-85 2-10 1-85
2-47 2-89 3-31 2-86
2-73 3-22 3-68 3-17
2-82 3-40 4-02 3-40
2-76 3-50 4-23 3-48
0-11 0-15 0-18 0-04
Head width (ram) Small Medium Large
0-4 35-7 37-5 37-1 37-3 37-8 0-3 36-1 37-8 37-9 37-9 37-8 0-3 36-6 38-6 38-6 38-5 38-0 Regression of head size on body weight Coefficient (mm/kg) 2-05 1-14 0-20 1-55 0-99 SE 0-22 0-19 0-16 0-16 0-32 1 Small—less than 2 SD from mean body weight at each age; medium—average body weight; large—more than 2 SD from mean body weight.
examined by analyses of variance. Rate of lay (eggs laid/number of bird days) was analysed on the logistic scale with extra-binomial variation (Williams, 1982). A split plot model with period of production (25 to 36, 37 to 48 and 49 to 60 weeks of age) was analysed to assess changes in rate of lay with age. The incidence of beak lesions and of different feather scores was evaluated assuming a linear model with Poisson errors. RESULTS
The rate of lay of females in pens without grids was higher than in those with grids, particularly during the period from 49 to 60 weeks of age. The difference between pens with and without grids on the logistic scale was 0-086 ± 0-039 (x2 (1 DF)50; P
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Assessment of the effects of separate sex feeding on the welfare and productivity of broiler breeder females P. M. Hocking
a
a
Agricultural and Food Research Council , Institute for Grassland and Animal Production, Poultry Department , Roslin, Midlothian, EH25 9PS, Scotland Published online: 08 Nov 2007.
To cite this article: P. M. Hocking (1990) Assessment of the effects of separate sex feeding on the welfare and productivity of broiler breeder females, British Poultry Science, 31:3, 457-463, DOI: 10.1080/00071669008417278 To link to this article: http://dx.doi.org/10.1080/00071669008417278
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
British Poultry Science (1990) 31: 457-463
ASSESSMENT OF THE EFFECTS OF SEPARATE SEX FEEDING ON THE WELFARE AND PRODUCTIVITY OF BROILER BREEDER FEMALES
Downloaded by [University of Illinois at Urbana-Champaign] at 00:56 16 March 2015
P. M. HOCKING Agricultural and Food Research Council Institute for Grassland and Animal Production, Poultry Department, Roslin, Midlothian EH25 9PS, Scotland Received for publication 28th September 1989
Abstract 1. The welfare and productivity of female broiler breeders were studied in pens containing 15 females and 1 male where the sexes were fed together or separately by means of a grid with 40 mm spaces over the female feeders. 2. Average head width did not increase after 25 weeks of age. 3. The rate of lay was lower in separate compared with mixed -sex-fed pens but egg weight was similar. 4. The incidence of swollen heads and beak lesions was higher and feather loss and rate of food intake was lower in separate compared with mixed-sex-fed pens. 5. It was concluded that the grid spaces should be 42 mm wide to avoid adverse effects on welfare and productivity.
INTRODUCTION
Fitting simple barriers to the feeding trough to exclude the males which have larger heads has made it possible to feed male and female broiler breeders different diets and quantities. The size of the gap through which the females feed is clearly of crucial importance. If it is too large, separate feeding of the sexes will not be achieved. If it is too small they will not be able to feed and productivity and well-being of the flock will deteriorate. As part of an experiment to compare the effect of different male diets and target body weights on fertility, groups of birds were fed in pens with or without gridded troughs. At the time this experiment was conducted, a gap size of 40 mm was recommended by the two major breeding companies in the United Kingdom. Several attempts to introduce separate sex feeding in the field were apparently unsuccessful (Laughlin, 1988). The purpose of this paper is to assess objectively the effect of these grids on rate of lay and several aspect of the welfare of the females and to make recommendations for the future. A full account of results in the males is given by Hocking (1990). 457
458
P. M. HOCKING
Downloaded by [University of Illinois at Urbana-Champaign] at 00:56 16 March 2015
MATERIALS AND METHODS
At 20 weeks of age, 6 rooms each containing 12 pens 3-6 m2 littered with wood shavings and containing 15 female and 1 male broiler breeders (Cobb 500, The Cobb Breeding Co. Ltd, Chelmsford) were established. Feeding and lighting followed the breeders' recommended schedules. The females were fed a conventional diet containing 11-5 MJ metabolisable energy/kg, 160 g crude protein (CP)/kg and 34 g Ca/kg. During lay, they were allocated a maximum of 160 g/bird d decreasing by 1 g/bird d, weekly after 36 weeks of age. Water was available ad libitum from three nipple drinkers. Food was supplied in a trough 1830 mm longX 100 mm wide X 100 mm deep, the edge of which was 280 mm from the floor. In two pens in each room males and females fed from the same open trough. Food troughs in the remaining pens were fitted with an L-shaped grid so that the birds were presented with a series of 40 mm gaps through which the females only could feed. The males in these pens were fed in tube feeders suspended too high for the females to reach. Males in two of these pens in each room were fed a low protein (110 CP/kg) diet ad libitum. Males in the other pens were fed 4 allocations of the two diets (160 and 110 CP/kg) which resulted in average body weights at 60 weeks of age of 3-1, 3-5, 3*7 and 3-9 kg. Body weight for males fed the low protein diet ad libitum was 5-0 and for the mixed-sex-fed males 5*5 kg. Eggs were collected daily from 24 to 60 weeks of age. Settable eggs from each pen were weighed in bulk on one day each week. Body weight was recorded for all females at 20, 26, 32, 46 and 60 weeks of age. At the same ages, the head width of a sample of three females in each pen was determined by one person using a pair of calipers at the posterior point of the lower mandible. The birds selected were the first to weigh within 100 g of the anticipated flock mean and the first to weigh more than, or less than, two standard deviations from the mean. In this way, the head widths of three groups of hens of different body weights (small, medium and large) were obtained at each age. Concern that lighter, more active, males may over-mate (Dudgeon, 1986) was assessed by comparing the condition of females in representative treatments. At 60 weeks of age the females in pens with the heavier separate-fed males (treatment 4, Hocking, 1990) and in the mixed-fed pens (one pen from each room) were scored for the loss of feathers caused by treading during mating. Each bird was scored as follows: no damage to or loss of feathers (5); damage to or loss of feathers on not more than half of the back (4); no feathers over most of the back extending to the top of the thighs (3); bare skin over the back and thorax (2); back, thorax and thighs denuded (1). Necrotic lesions and erosion of the nares, mandible and maxilla were scored, separately, on all females at 60 weeks of age. The rate of food consumption by females in pens with and without a grid was determined at 60 weeks of age after the males had been removed. One pen of each type was selected at random in each room. The troughs were weighed before feeding (138 g/bird) and again 1, 3, 7 and 24 h afterwards. Data for food intake, body weights, head width and egg weight were
SEPARATE SEX FEEDING
459
TABLE 1
Body weight and head width of broiler breeder females and regression coefficients for head size on body weight
Category1
Downloaded by [University of Illinois at Urbana-Champaign] at 00:56 16 March 2015
Body weight (kg) Small Medium Large All females
Age (weeks)
SED
20
25
32
45
60
1-63 1-85 2-10 1-85
2-47 2-89 3-31 2-86
2-73 3-22 3-68 3-17
2-82 3-40 4-02 3-40
2-76 3-50 4-23 3-48
0-11 0-15 0-18 0-04
Head width (ram) Small Medium Large
0-4 35-7 37-5 37-1 37-3 37-8 0-3 36-1 37-8 37-9 37-9 37-8 0-3 36-6 38-6 38-6 38-5 38-0 Regression of head size on body weight Coefficient (mm/kg) 2-05 1-14 0-20 1-55 0-99 SE 0-22 0-19 0-16 0-16 0-32 1 Small—less than 2 SD from mean body weight at each age; medium—average body weight; large—more than 2 SD from mean body weight.
examined by analyses of variance. Rate of lay (eggs laid/number of bird days) was analysed on the logistic scale with extra-binomial variation (Williams, 1982). A split plot model with period of production (25 to 36, 37 to 48 and 49 to 60 weeks of age) was analysed to assess changes in rate of lay with age. The incidence of beak lesions and of different feather scores was evaluated assuming a linear model with Poisson errors. RESULTS
The rate of lay of females in pens without grids was higher than in those with grids, particularly during the period from 49 to 60 weeks of age. The difference between pens with and without grids on the logistic scale was 0-086 ± 0-039 (x2 (1 DF)50; P
