I don't have any mini-proof/mini-safe pasture fencing, so mine are on drylot most of the time and I use portable panels for daytime grazing around the "yard" (where we stack winter hay for the cows, hay isn't brought in til fall). My main drylot is 48x100' and houses 5 minis, a second drylot is the same size and houses 3 minis (they choose to spend most of their time in the shelter and a few times a year their outdoor pen is used for working cows, so they are shut in the shelter at those times), 2 minis share a 48x48' pen and one stallion has a 12x48' pen. These sizes seem to work for me, but like most, more space is always nice.