Assessing the welfare consequences of providing litter for feed-restricted broiler breeders

Abstract

1.	Broiler breeder females were fed restricted allocations of a standard wheat–soy ration to meet target body weights. They were housed on raised plastic slotted floors (S) or wood shavings litter (L) from hatch to 8 weeks when each pen of 12 birds was transferred to another pen in the same block in a 2 × 2 factorial experiment (LL, LS, SL and SS). Measures of bird welfare were taken at 4 weeks of age, and at 9 and 10 weeks following transfer to the new pens.
2.	At 4 weeks of age, birds reared on S spent more time standing, pecking the feeder, the wall and other birds and less time pecking the floor compared with those on L. Gentle feather pecks, strong feather pecks and strong feather pulls were more common in S than L.
3.	Mean body weight was higher and coefficient of variation lower in birds on L than S at the end of the experiment. Feather loss and damage scores at 10 weeks were higher for birds reared from hatch to 8 weeks on S.
4.	Birds that were reared on S continued to peck more at the pen walls after transfer to new pens but there was no other carry-over effect on behaviour. Birds on S at 9 and 10 weeks pecked more at the walls and less often at the floor, and rested less often. There was more feather pecking on S than on L in the second week post transfer.
5.	Tonic immobility was greater and plasma corticosterone concentrations were lower at the end of the experiment in birds on L than S at 9 and 10 weeks of age. The heterophil–lymphocyte ratio was similar between treatments at 4 weeks and after the birds were moved to a new pen.
6.	The results are consistent with the view that litter and wall pecking has de-arousing properties and that this activity is re-directed foraging that diminishes the stress of feed restriction.

Acknowledgements

We are grateful to Graeme Robertson, Vanya Zaczek, Richard Hunter and Laura Summers for excellent technical assistance. The chicks were provided with assistance from Yves Jego of Hubbard, France. This work was supported by a European Community grant (QLRT-2000-1732). Roslin Institute receives funds from the BBSRC.