I had 2ft X 8ft runs made from pallets and a pc of wood over the top for a pair for a while... (one had a trio) They seemed really comfortable, no picking issues or real fighting... I also had one with two imature boys in it and they were ok?? (I liked it cause it was quick, easy to screw together and temperary, but had good space) They were in there about a month and are currently 16 weeks old.
Just a thought
Patricia