Effects of open water and non-water enrichment on welfare and microbial exposure in grow out Pekin ducks

This study evaluated the effects of four enrichment treatments Nipple line (CON, control), Whiffle ball (EED, non-water enrichment), Preening cup (PC, semi-open water), and Pekino (PEK, open water) on the welfare, behavior, bacterial exposure, and microbiome composition of Pekin ducks. Behavioral and welfare assessments revealed that EED and CON treatments promoted better feather cleanliness, nostril health, and foot pad scores, while PEK and PC increased litter moisture and reduced feather cleanliness. PEK ducks showed increased preening behaviors with larger uropygial glands, while PC ducks exhibited resource guarding and aggression. Microbial analyses showed that EED exhibited lower alpha diversity but higher abundances of Pseudomonas and Achromobacter at baseline, while PEK and PC were associated with increased Moraxella levels. By 6 hours, Pseudomonas levels increased in CON and EED, and Acinetobacter became predominant in CON. Functional profiling indicated elevated metabolic pathways in PC and EED at baseline, particularly in aerobic respiration and amino acid biosynthesis. These findings suggest that while water-based enrichments (PEK and PC) encourage natural behaviors, they pose higher bacterial exposure risks, whereas non-water enrichment (EED) and closed water systems (CON) provide more stable microbial environments and better welfare outcomes.