It is not cruel and once they get used to it they actually like them. It's their little home. Ours will even go in their crates sometimes on their own when they want some peace and quiet. We crate ours when we are not home. It is actually safer for them to be crated. It keeps them from getting into things they should not and even keeps them from chewing an electrical card. The wire crates are better for bullies, as they have better air circulation then the plastic crates so they will not get hot in them.