like its been said you may need more ferrets down the holes or it could be there not going deep enough ,you find a really good ferret goes deep becouse thats were most rabbits are hideing and its not really down to how many holes you have but how far apart the holes are that makes you put more ferrets down,plus a ferret that knows it suff will bolt rabbits that some ferret wont bolt ,if you have a young jill that just sniffs the rabbit the rabbit will more likely just puff its self up stopping the ferret from getting past ,so the young ferret just walks on were the ferret that knows what its