i ave owned some good little bolters. also a few that i was digging to regular. 1 jill in particular. she could bolt them fine but always had to be dug to also. if i dig to a ferret my own choice is that i like a ferret to stay with its kill so i can locate it and the rabbit. i value both types.you cant guarantee what ferrets are going to turn out like.1 litter i bred some made good bolters some seemed the type to be dug to regular. these were all jills given to a few people i know.in shallow burrows i dont mind. if it is a known deep place for my area. the jill mentioned would not be used. p