Effect of Pen Size on Stress Responses of Stall-Housed Horses Receiving One Hour of Daily Turnout.

The research study investigates the impact of pen size on the stress levels and behavior of horses housed in stalls but given a daily one-hour period of organized group turnout. The study found that larger pens seemed to reduce stress levels and aggressive behavior among the horses, suggesting the size of the turnout area has a significant effect on well-being in horses during these periods.

Research Method

• The analysed sample consisted of a herd of 12 horses that were split into groups of four.
• Each group was kept in a stall for 24 hours before being given a one-hour period of free movement (“turnout”) in one of three differently sized pens. Each pen offered different space per horse: 342 square meters, 263 square meters, or 184 square meters.
• The groups were rotated through the varying pen sizes over three days, exposed to each environment once per day.
• The study monitored the levels of cortisol (a stress hormone) in the horses’ blood at several points: in the morning before the turnout, 15 minutes into the turnout, an hour into the turnout, and an hour after returning to the stalls.
• Aggressive and threatening behavior of the horses was also recorded, classified as agonistic behavior (chasing, contact biting, and kicking) and low-level threats (pinned ears, tail swishing, and threats of biting or kicking).

Findings

• The research found that horses in larger pens (providing 342 square meters per horse) had reduced cortisol levels 15 minutes into the turnout and one hour after returning to their stall, implying lower stress levels.
• Horses in the smallest pen space (184 square meters per horse) were found to engage more frequently in aggressive and threatening behavior, compared to horses in larger pens.

Implications

• The results of the study are significant to animal welfare as they suggest that the size of the turnout area plays a significant role in minimizing stress and aggression among horses.
• The findings suggest that providing at least 342 square meters of space for each horse could decrease chances of injury and promote the overall well-being of the horse during group turnout sessions.