That is 56sqft, if they are small bunnies it may be okay. If you could have the run wider than 4ft that would mean a much bigger place for them to run about in, as its not very wide. I have my two buns in 60sqft (6x2 hutch and 8x6 run) and I would put 3 2kg-ish size buns in there, but I dont think they'd get as much exercise in a narrower run.