Effect of outdoor structural enrichments on the performance, use of range area, and behavior of organic meat chickens

Chickens provided with outdoor access often do not fully use the range area. Natural cover, such as trees, can provide shelter and increase range use, but may not be practical for use in all free-range operations. A study was conducted to determine whether constructed enrichments that simulate natural structures increase range use and impact behavior of meat chickens. Slow-growing Delaware chickens were raised in floor pens (17 birds/pen) in a naturally ventilated house, with a pophole in each pen that allowed daily access to a vegetation-covered outdoor area. Feed and water were provided inside and outside. Birds were randomly assigned to one of 2 treatments: no range enrichment (control; NON) or range enrichment (ENR), which had roosts made of plastic pipe or screened shelters placed 7.6 m and 22.9 m from the house and overhead shade panels at 15.2 m. There were 4 replications. The numbers of birds inside and in the 4 quadrants of the range were counted in 7-min intervals 3 times daily (0900 h, 1300 h, and 1600 h) for 3 consecutive d when the birds were 7 and 10 wk of age; the numbers of birds performing various behaviors also were counted. On average, only 12.9% of birds used the range at any given time. The behavior of the birds was strongly affected by location (inside vs. outside), with birds mainly foraging and walking while outside and feeding, standing, and sitting while inside. Time of d impacted the number of birds that ranged (currency sign 0.0001), with fewest birds outside during mid-day. Overall, birds using the range were most often (71%) observed in the quadrant nearest the house (zero to 7.6 m). However, in the ENR treatment, more birds (13%; currency sign 0.0001) were observed in the farthest 2 quadrants (15.2 to 30.5 m from the house) than in the NON treatment (6%). This indicates that adding constructed enrichments to the range encouraged meat chickens to use it more fully.