Adult-hen microbial contact changes broiler resilience without raising live weight

A study published on 10 October examines whether early microbial contact with adult hens can influence broilers’ response to stress. The question matters because commercial chicks are normally raised without adult birds, meaning early intestinal colonisation is largely shaped by the housing environment.

The experiment involved 128 day-old broilers. One group had contact with adult hens until day 10, after which the hens were removed. On days 18 and 20, some birds received lipopolysaccharide to induce an inflammatory stress response. Researchers measured body weight, cecal microbiota, metabolites and gene-expression markers in the intestine and liver.

The contact did not alter body weight or ileal histomorphology. It did, however, significantly reshape cecal microbial diversity and composition, was associated with higher volatile-fatty-acid production and changed tryptophan metabolism. Molecular signals also indicated changes in intestinal-barrier and antioxidant-defence pathways. Under lipopolysaccharide challenge, prior microbial contact attenuated some host responses associated with stress.

The practical conclusion requires caution. This is not an immediate recommendation to place adult hens with commercial broiler flocks, nor does it demonstrate better carcass or meat quality. Its value lies in separating production performance from biological robustness: an intervention may not add live weight but can still alter how birds respond to immune stress. Commercial application will require trials under field conditions, biosecurity protocols and outcomes covering welfare, losses and final product quality.