ive got 3 hutches at the minute, one 5x3x5 for my hob which i made myself, its got two floors connected by a ladder, the upstairs being its 'bedroom' and feeding area and the downstairs has things for him to play with.
one 6x2x4, again connected by ladders, a 'bedroom' on each floor and an area for feeding and playing.
i then have a much smaller 2x1.5x2 which i used when one of my kits was ill just to seperate it to make sure it was getting enough food and rest from the other little buggers! haha
im planning on attaching the smaller hutch to a run which im going to make soon so tha