Evaluation of Short-Term Stall Size Housing on the Behavior and Welfare of Domestic Horses (Equus caballus).

Overview

• This study evaluated whether domestic horses housed in slightly smaller-than-recommended stalls (136 ft²) showed differences in behavior and welfare compared to horses housed in standard-sized stalls (144 ft²).
• Various physiological and behavioral indicators were measured to assess if the smaller stall negatively impacted the horses’ welfare during short-term housing periods.

Introduction and Background

• Single-stall housing is widely used for managing horses in settings such as racing stables, riding schools, and research facilities.
• Adequate stall size is important for allowing horses to lie down and change posture, which are essential for rest and overall welfare.
• The commonly recommended stall size for laboratory horses is 144 ft² based on guidelines.
• Not all housing facilities meet this recommended size, and there is limited scientific evidence supporting the welfare benefits of this exact standard.

Study Design

• The study used a crossover design involving eight horses grouped into four pairs based on social preferences.
• Within each pair, one horse was randomly assigned to either the standard-size stall (144 ft²) or the smaller stall (136 ft²) for 4 days.
• After 4 days, horses were given a 9-day turnout period to pasture, following which each horse was switched to the alternate stall size for another 4 days.
• This design allowed each horse to serve as its own control to directly compare effects of stall size on behavior and welfare.

Measures and Methods

• Physiological measures:
• Hay consumption was recorded daily to monitor feeding behavior.
• Fecal output was measured as an indicator of digestion and health.
• Serum cortisol concentration was assessed as a biomarker of stress.
• Behavioral monitoring:
• Accelerometers were used to record movement and quantify duration of lying down (sternal and lateral recumbency).
• Continuous video recording (~96 hours per horse per stall condition) was obtained to assess various behaviors.
• Behavioral data were scored every 5 minutes and included resting, locomotion, standing, eating, drinking, elimination, and stereotypic behaviors.

Results

• Physiological markers:
• No significant differences in hay consumption or fecal output were observed between horses housed in the smaller versus the standard-sized stalls.
• Cortisol levels were similar for both stall conditions, indicating no measurable increase in stress due to stall size.
• Behavioral findings:
• No difference between stall sizes in the duration of sternal or lateral recumbency, as measured by accelerometer or video analysis.
• The only significant behavioral difference was that horses spent more time walking when housed in the smaller stalls (136 ft²).
• No differences were found in behaviors such as rolling, standing, resting while standing, eating, drinking, or exhibiting stereotypic behaviors.
• Some behavior measures varied across days regardless of stall size, but these changes affected both groups equally.

Conclusions

• This study suggests that a slight reduction in stall size from 144 ft² to 136 ft² for short-term housing does not adversely affect key welfare indicators in domestic horses.
• Horses maintained normal feeding, fecal output, resting behavior, and stress hormone levels in both stall sizes.
• Increased walking in the smaller stalls may indicate subtle behavioral adaptation but did not translate into negative welfare outcomes.
• The findings provide evidence that slightly smaller stalls than recommended guidelines may be acceptable for short-term housing without compromising equine welfare.
• Further research could investigate longer-term effects and explore whether similar results hold for different populations or housing practices.