Responses of Laying Hens to Full vs. Partial Litter Access inAviary Housing

摘要

Cage-free egg production has been a topic of increasing attention in the USA over the past two years. With different cage-free styles and management schemes, retailers have developed their own cage-free criteria. One highly debated aspect is if hens may be kept inside the system for part of the day, during the firstfew hours after lights-on. Research is lacking regarding the impact of such practice on hen well-being, production performance, and environmental conditions. The objective of this study was to evaluate the effects ofproviding full litter access (i.e. doors always open) vs. partial litter access (i.e., doors automatically opened 5 hr after lights-on), coupled with the absence or presence of experienced hens (1.5% of population) on the following variables: a) incidence of floor eggs, b) birds remaining on litter floor at night, c) bird mortality, d) body weight and uniformity, e) ammonia level in the barn, and f) amount and moisture content of floor litter. A commercial aviary henhouse (51,405 Dekalb White hens) was divided into 32 sections for the four treatments (8 replicates per treatment). Results show that sections with full litter access had considerably higher incidences offloor eggs, more manure deposition on the floor, and higherammonia levels in winter, as compared to the partial litter access sections. Inclusion of experienced hens in the young flock did not reduce floor eggs. The percentage of hens remaining on the floor at night was low (<0.01%) for all treatments from 24 weeks of age onward.