My wife went to check on the girls and a 6' black snake was in the nesting box with an egg sized bulge in his "throat" . She didn't want to shoot it in the coop so she shooed it out. Unfortunately it was quicker than she expected. She got a couple shots off but doesn't think she hit it. Is there anything to keep them out--chemical, odor etc.? I've seen snake repellent but heard it may not be effective. May have to just wait and see if it comes back and be better prepared to get rid of it.