The size of my cage is three grids by 8 grids. Roughly 25 square feet. I have four boars. The oldest, nugget, is chasing and biting the backs of the younger pigs. They've lived together in this grid pen for about four months and all of a sudden nugget is biting my two middle piggies. He snuggles the youngest. Should I build a bigger pen for them? They've always gotten along this far.