I don't have a rat colony but do hold onto the feeders that don't get eaten. Seldom would I have escapees but when they do get out it's because they jumped out of my reach or quick darted away. I used to chase them around, now there is a rat terrier living with me who helps with the task of chasing and catching. It would be more fun if he actually fetched them for me and didn't play with them like a cat, but it can be amusing. So far no deaths and a lot of slobber as he likes to play with them. Rodent-chasing dogs actually are useful.