You have an established group of horses that are primarily stalled that you want to provide with group turnout. What is an appropriately size paddock (with a little grazing) or pen (dry lot with no grazing) that will work for your equids? You want to give them enough space to reduce aggressive behavior while allowing exercise and interaction.

Researchers looked to answer these questions in a small study published in 2021 in the Journal of Equine Veterinary Science¹.

While group turnout is important to socialization, injuries can happen when horses work through dominance scenarios.

The Study

The investigators wanted to determine an appropriate paddock size for group turnouts. They took a dozen horses from a single herd and divided them into groups of four. Horses were stalled for 24 hours, then turned out for 1 hour into one of three differently sized pens.

The pens provided room of 342, 263, or 184 m² per horse. That translates to 3,681, 2,831, or 1,981 square feet per horse.

The groups of horses were rotated through the various-sized pens over three days, receiving one ‘treatment’ per day.

Blood was sampled for cortisol (a stress hormone) concentrations at 8 each morning and at 15 and 60 minutes into the turn-out sessions. It was sampled again 60 minutes after the horses were returned to individual stalls.

The groups rotated through three turnout times, at 9 a.m., noon, and 2 p.m.

The researchers counted the agonistic behaviors (chasing, contact biting, and kicking) and low-level threats (pinned ears, tail swishing, bit and kick threats).

Study Results

In the larger pens, horses had lower plasma cortisol concentrations by 15 minutes after turnout and at 1 hour after being returned to their stalls.

Horses in the smallest pens had greater agonistic and low-level threat behaviors than horses in larger pens.

“These data provide insight into appropriate pen sizes for horses from established herds,” noted the researchers. “Providing at least 342m² (3,681 square feet) per horse may reduce the chance of injury in horses accustomed to group turnout.”

Final Words

The authors of this research noted that because horses are social animals, they benefit from physical interaction with each other. Research has shown that social isolation in horses increases cortisol concentrations, locomotor behaviors, and oral stereotypies.

However, many horse properties have small land allotments. That means group turnout might only be possible in small paddocks for short periods of time. “Therefore, we endeavored to investigate ideal minimum paddock size requirements for horses in group turnout,” the authors noted.

Reference

1. Effect of Pen Size on Stress Responses of Stall-Housed Horses Receiving One Hour of Daily Turnout. 2021. Jessica K. Suagee-Bedore, Daniel R. Linden, Karen Bennett-Wimbush. Journal of Equine Veterinary Science