Some schools of though are calling for penning pigs together in larger groups. A study by University of Illinois researchers takes a look at floor space, large versus small groups, multiple versus a single feed location and how they all interact.

The researchers conducted two experiments, the first to quantify the effects of and interactions between group size and space allowance on weanling pig performance. The study compared groups of 20 pigs versus groups of 100 pigs, as well as testing two different floor space allowances.

Floor space allowances were kept constant for the first four weeks after weaning and then increased for the next five-week period.
To determine the amount of floor space to use as the "reduced space set", researchers subtracted half of the free-space from the control-space requirements. Pig weights at the end of the forth and ninth week were estimated at 14 kg and 45 kg, respectively, and were used to calculate the free-space requirements.

Results seem to indicate that penning weanling pigs in larger groups lowers weight gain and increases variation in body weight. Also, reducing floor space reduces weight gain, but required floor-space allowances appear to decrease with increasing group size.

The second experiment was conducted to evaluate the effects of feeder location in large pig groups. The study was comparing multiple vs. single-feeder locations.

This study compared a large group with a single-feeder location, a large group with multiple-feeder locations and a small group with a single-feeder location.

While, average daily gain and feed intake were lower for the two large pig groups than for the small group, the effect of multiple feeders did not improve or reduce performance.