The only problem I can foresee with putting all three bunnies into one carrier is the weight of the damn thing. I struggle to carry just two big bunnies in one cage :shock:. When I take all four to the vets at once, I stack two cages one ontop of the other and strap them to my doggie-stroller!!! Then we wheel ourselves into the surgery like a nutty Hollywood starlet with a chihuahua in a pink tutu :shock:.