i have a 6 foot x 4 foot shed which houses my herd of piggies, with permanent access to an outside run with slabbed base (keeps their nails in tip top condition) which is 6.5 foot x 5 foot, so a total of around 55 square feet. they have a thick 4-6 inch layer of woodshavings on the shed floor, and hay aswell. do you think this is ok for a herd of 16 or should i make things larger?