Outdoor stocking density and free-range broiler welfare


Author: Hannah Phillips, graduate student, College of Food, Agricultural and Natural Resource Sciences (CFANS)

Quick facts

  • Free-range broilers with less outdoor space may sunbathe, aggressively attack, stretch, or pant more than those with more outdoor space.
  • Extra outdoor space may slightly improve broiler welfare, but the quality of outdoor space is likely more important than its size.
  • Free-range broilers should have access to shade structures and an ample amount of forage cover.

Outdoor access for free-range broilers

Free-range broilers require outdoor access. Many believe that more outdoor space improves broiler welfare, but there is little research to support this idea. Therefore, in our study, published in the journal Animals, we evaluated if the amount of outdoor space affects broiler welfare.

How we conducted the study

In this study, we raised Freedom-Ranger broilers at high (5 sq. ft. per broiler) and low (27 sq. ft. per broiler) outdoor stocking densities. We evaluated behaviors and feather damage from 5 to 11 weeks of age.

View of high (left) and low (right) outdoor stocking densities. The two groups had a covered mobile shelter of equal size.

What we found


Sunbathing and aggressive attacks were greater in broilers that had less outdoor space. Stretching was greater in broilers with less outdoor space only at 8, 9 and 10 weeks of age. Panting was greater in broilers with less outdoor space only at 6 and 9 weeks of age. Outdoor space did not affect the remaining 8 behaviors. Broilers with less outdoor space may have used sunbathing, stretching, and panting to cope with discomfort.

Means (± 95% CI) for 10 behaviors averaged over 5 to 11 weeks of age. Diverse behaviors were observed at both outdoor stocking densities.

Feather damage

Broilers that had less outdoor space had greater tail feather damage, but outdoor space did not affect wing feather damage. Greater aggressive attacks in broilers with less outdoor space may partly explain the increase in tail feather damage. Recent research shows that aggressive behaviors are more likely to occur outdoors in free-range broilers. So, perhaps broilers raised at a low outdoor stocking density were able to avoid aggressive conflicts because they had more outdoor space.

Probabilities (± 95% CI) for feather damage averaged over 5 to 11 weeks of age.