How much floor space do group housed sows need?

An article from our colleagues in the College of Food, Agricultural and Natural Resource Sciences, and published in the National Hog Farmer explores how much space the sows really need. It is critical to find the right balance between the welfare of the animals and the productivity of the farm.


  • determine the minimal square footage needed to house the sows. Surfaces studied were 22, 20, 18, and 16 square feet.
  • assess if giving more floor space during the first days when the sows are mixed (22 square feet) and then reducing it to 16 square feet when the hierarchy is established was an efficient strategy.
  • evaluate the usability of accelerometers to monitor sow postures.


There was no difference in any of the production parameters followed in this study based on the floor space allowance. More interestingly, floor space allowance did not influence the duration of fighting or its frequency when the sows were establishing dominance.

However, the more space allowance was given to the sows, the more lameness was observed on the farm. The highest lameness prevalence was found in sows for which space allowance was reduced from 22 to 16 square foot after hierarchy was established.

Parity did not influence the results meaning that younger and older sows reacted similarly to the difference floor space allowances.

Accelerometers were found to be a reliable method to monitor the posture of the sows if they were laying down on their side or standing. When the sows were laying on their sternum, the device was correct only 54% of the time.

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