title: Feeding motivation on the incidence of floor eggs and extraneously calcified eggs laid by broiler breeder hens.
abstract: 1. Commercial broiler breeder hens lay many eggs on the floor rather than in nest boxes provided. A study was conducted to determine whether feeding feed-restricted broiler breeder hens during the sitting phase of nesting results in a higher incidence of floor eggs and/or retained eggs. 2. Sixty broiler breeder females (Ross 308) were randomly assigned to 6 deep litter pens containing 10 nest-boxes. At 35 weeks of age and for 9 weeks, feed was distributed to all pens at lights-on every second day (fed normally, FN). On alternate days (feeding delay, FD), feed was distributed when 2-3 hens/pen were sitting in a nest box. Behaviour was sampled at 41 weeks of age, for 26 d. Eggs and egg location data were collected daily, and eggs were scored for extra-cuticular calcium. 3. Of 81 instances in which the hen was sitting firmly in a nest box at the time of feeding, on 80 instances the hen left the nest-box to feed, and on one instance the hen laid her egg then exited to the feeder. Of these 80 instances, on 58 occasions the hen returned to a nest-box to lay her egg; on 12 the hen returned to the nest-box but laid no egg; on 7 the hen did not return to the nest box and laid no egg; and on three the hen laid her egg on the floor. 4. Mean floor egg percentage was 13·3 ± 3·2% on FN and 13·3 ± 4·7% on FD days; these did not differ significantly. 5. The mean extra-cuticular calcium score over all pens was 0·9 ± 0·06 on FN days and 1·2 ± 0·06 on FD days; these differed significantly. 6. In conclusion, feeding broiler breeder hens during nesting results in a conflict between feeding and nesting motivation and higher numbers of extraneously calcified eggs, but does not result in a significant increase in floor eggs even though nesting hens will leave the nest box for food.
authors.affiliation: Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada. ksheppar@uoguelph.ca
authors.forename: K C
authors.initials: KC
authors.lastname: Sheppard
authors.forename: I J H
authors.initials: IJ
authors.lastname: Duncan
mesh_terms: D000821:Animal Feed; D000818:Animals; D001522:Behavior, Animal; D002118:Calcium / Q000032:analysis; D002645:Chickens / Q000502:physiology*; D005260:Female; D009425:Nesting Behavior; D010058:Oviposition; D010063:Ovum; D013997:Time Factors
chemical_list: D002118:Calcium