Twenty-four commercial broiler flocks were used for this study,
which was conducted on a single site in the U.K. Four identical
houses were studied simultaneously, with six replications over
time, between October 2010 and June 2011.
Animals and Husbandry
Broiler chickens of mixed sexes and of one of two commercial
broiler breeds were placed in the houses as day-olds
(33 000e35 000/house) and grown to 35 days old with a target
final stocking density of 38 kg/m2. Each house was 1670 m2 and
contained 488 feed pans and 1735 water nipples. Ventilation was