hay bathing

Hey there, I have 5 piggies and I have noticed especially in the last 5 weeks that they all like to take a big nap in the hay. I have a 7x3 cage + an extra 1x3 room for hay, and they all like to go in there and take a big nap, but not at the same time, maximum 2 at the time. Whenever 3 or more...