Economic and welfare benefits of environmental enrichment for broiler breeders.

Designs to enrich the environment are crucial in the effort to fully address the biological needs of domestic animals. Although enrichment programs have been shown to improve health and welfare, little is known of their potential for application to commercial broiler breeder environments. We investigated the potential benefits of cover panels for broiler breeder reproductive performance in a commercial setting. This demonstration trial occurred on 5 commercial broiler breeder farms, each with a control and panel treatment room containing approximately 7,000 females and 800 males. Reproductive performance was measured from 25 to 60 wk by the number of eggs laid per female per week as well as weekly fertility and hatchability rates. The location of marked males was recorded weekly to quantify male movement. Access to cover panels improved egg production by 2.1% and maintained better hatchability and fertility throughout the breeding cycle (significant interactions of age and panel treatment) leading to an additional 4.5 chicks/female. Male home ranges, based on minimum convex polygons, were larger in the enriched (259 +/- 24.4 m(2)) vs. control flocks (184 +/- 23.1 m(2)). Providing enrichment in the form of cover panels improved reproductive performance, most likely by increasing males' mating opportunities and reducing female stress. We found a clear economic benefit to providing enrichment, an estimated $3 million if all breeder houses within the participating company were outfitted with the panels. These results demonstrate that environmental enrichment is not only beneficial for broiler breeder welfare, but can also be economically advantageous, resulting in a win-win situation for poultry welfare and production.

Space use according to the distribution of resources and level of competition.

The manner in which an animal moves throughout and utilizes the space available to it depends on the dispersal, availability, and level of competition for resources the animal requires for its biological functioning. We tested groups of broilers (Gallus gallus domesticus) in 3 experimental group sizes of 5, 10, and 20 individuals per group under 3 resource distribution patterns. Groups were tested with access to 1 large single feeder, 2 medium-sized feeders, or 4 small feeders. In all arrangements the total amount of food available per bird remained constant. During the first phase groups had free access to all available feeders, and in the second phase access at each feeder was restricted to a single bird. Space use, measured by calculating core areas and interindividual distances between group members, increased as group size grew larger and as feeders became more widely distributed. Not all group sizes responded equally to the resource distribution patterns. Space use patterns for the smaller group sizes were more strongly affected by resource distribution patterns than the larger group sizes. When access to the feeders was restricted, consumption, aggression, and space use increased. Broilers adjusted their space use and aggressive behavior according to the level of competition, dictated not only by group size but also resource distribution and accessibility.

Patch discrimination as a function of handling time.

We tested male broiler chickens in 3 experimental group sizes (GS) to examine the mediating effects of GS and feed handling time on patch choice. We tested the experimental GS in a 3-patch discrimination trial with patches that contained identical amounts of feed but differed in the proportion of inedible filler material (wood shavings) added. The patch requiring the least handling time offered the highest profitability and was composed of 25% filler and 75% feed (by volume), whereas the mid and low profitability patches contained 50 and 75% filler, respectively. Food consumption, foraging duration, patch residence time, number of foraging bouts, and number of discrete patch visitors were significantly greater at the more profitable patches, requiring less handling time. We found a greater number of birds exploiting all 3 patches at larger GS, although we did not detect a parallel increase in aggression. On the contrary, aggression increased only as handling time decreased. These results suggest that at large GS resource monopolization did not occur; birds were most likely involved in scramble competition, particularly at the more profitable patches. Our findings show that broilers are able to discern the handling time required to obtain nutritious feed and adjust their foraging behavior according to the number of competitors.