i think if a dog cantget up to what ever is in the hole if hes to big i personally woulndt keep them to big. but if a dog goes in and gets a nick and comes back well i wouldnt have him to be honest. i had a patterdale dog a good little dog. he never shyed back, but i dug him two hard digs in a week. the second time he came out after hour but it was my fault he was two sore. i dug him numores times after that and he never did that