I am sure mice DO live in barns.
But I am also sure this person was in over his head with feeder breeding and reptiles. That happens to some people. They start out wanting to help a few kittens and soon enough they have 657 cats crapping and pissing all over their home. Same with reptiles. Some people get one and think the care is "so easy" and they don't stop getting more and more and more and soon enough they are over run. Normal people would stop at that point, but others like this guy keep going because the thought of telling people you can't handle it anymore or someone taking them away is worse than doing whats right.