It's funny this topic should come up now. This morning when I checked my mice I found this one little dude trapped; he had been able to go in and out of this feeder yesterday but not today! I had to cut the wire with a pair of wire dykes to free him. He was okay, just a little subdued. Fortunately not many youngsters think of doing this. I scattered some blocks on the cage floor to hopefully make them less inclined to try to get inside the feeder.