Broiler Chicks’ Motivation for Different Wood Beddings and Amounts of Soiling

SIMPLE SUMMARY: Many animals move excreta—or feces—away from resting areas to avoid attracting predators and spreading disease. However, today’s farms raise broiler (meat) chickens in large barns with stocking densities that prevent the birds from segregating their excreta. Moreover, whether or not chickens would prefer to avoid their excreta is unknown. Understanding what litter conditions chickens prefer can help inform farming practices. Therefore, this experiment aimed to assess chicks’ motivation to access unsoiled bedding or soiled litter. We used six pens of six to seven broiler chicks—each pen divided into two compartments by a barrier containing two one-way push-doors. The ‘home’ compartment contained soiled wood shavings, while the ‘treatment’ (T) compartment contained either aspen wood shavings, pine and spruce wood shavings, soiled pine and spruce wood shavings, ammonia reductant treated soiled pine and spruce wood shavings, or a feed treatment as a gold standard. To determine the chicks’ motivation to access the resources, the door leading into T weighed 0% (lifted), 10%, 20%, or 30% of the chicks’ body weight. The combination of time spent in T, number of visits to T, and average maximum weight pushed to access T were used to measure motivation. Chicks showed equal motivation for all substrates and preferred feed over all substrates. However, future experiments must explore chicks’ preference and motivation over the long-term in commercial conditions. ABSTRACT: In the wild, excreta soiled surroundings can attract predators and spread disease. Yet, farmers rear broiler chicks in large barns with stocking densities that prevent excreta segregation. To measure chicks’ motivation to access unsoiled bedding or soiled litter (collectively, substrates) we used 40 16-day-old broiler chicks who were divided into six two-compartment pens. The ‘home’ compartment (H) contained soiled wood shavings, while the ‘treatment’ compartment (T) contained either aspen wood shavings, pine and spruce wood shavings, soiled pine and spruce wood shavings, ammonia reductant treated soiled pine and spruce wood shavings, or a feed treatment as a gold standard. The barrier separating the compartments had two one-way push-doors that chicks pushed to access a resource. The chicks’ motivation was measured by the average maximum weight pushed to access each resource. The door leading to T weighed 0% (raised), 10%, 20%, or 30% of the chicks’ body weight, and chicks could return to H via a raised (for 0%) or unweighted door. Our findings indicate that chicks worked hardest for feed, but paid a lower, equal price to access all substrates. With increasing door weight, chicks visited less and spent less time with the substrates. Therefore, as chicks themselves do not avoid litter that could have potential negative effects on their well-being, it is important that farmers diligently monitor litter conditions as their primary care-takers.