Multifunctional elevated platforms for improving thermoregulation, litter quality and welfare in broiler chickens.

Elevated structures are rarely provided as environmental enrichment in intensive broiler production systems, despite their potential animal welfare benefits, by enabling birds to avoid body contact with soiled litter, and by accommodating behavioral needs such as resting and perching. To further increase the broiler welfare benefits, multifunctional elevated platforms were developed with three additional functionalities: a manure collection system, a local cooling system, and a dark-sheltered area. This study evaluated the effects of multifunctional platforms on litter quality and multiple welfare indicators under thermoneutral and heat stress conditions in broilers. Three production rounds were conducted, each involving 560 one-day-old male chicks (Ross 308), equally distributed over four pens and reared for 43 days. The facility had two separate compartments: one maintained under thermoneutral conditions and one exposed to heat stress. Each compartment contained one platform-enriched pen and one barren pen. Heat stress was induced by increasing the ambient temperature to 32°C for 6 hours per day from day 29 to day 40. Litter quality was scored and manure on the trays was weighed weekly. At the end of the production round, the dry matter content, pH, and electrical conductivity of the litter were assessed. At d43, birds were scored for plumage cleanliness, footpad dermatitis, and hock burns. Fearfulness was evaluated at d8 and d39 using the human avoidance and novel object tests. The platforms did not affect objective litter quality measures, except for improved subjective litter scores during the grower phase (p < 0.001). Plumage cleanliness was improved by heat stress (p < 0.001) and with platform access (p < 0.001). Under heat stress, the platforms reduced the prevalence of footpad dermatitis (enrichment × temperature: p = 0.002) and hock burns (enrichment × temperature: p = 0.036). Broilers in enriched pens were less fearful, as indicated by shorter human-avoidance distances at day 8 (p = 0.019) and more birds approaching the novel object at day 39 (p = 0.043). Heat stress increased fearfulness, with fewer birds approaching the novel object at day 39 (p = 0.022). In conclusion, even without strongly affecting litter quality under the conditions of this experiment, the prototype platforms improved key indicators of broiler welfare, particularly when exposed to heat stress.