NO. Is it cruel to leave them for hours in a crate? OF COURSE!! But the puppy should be able to spend an hour or a small amount of time in a kennel, crate, or exercise pen and take a nap. You must have some confinement area for the pup while you are training him/her. A playpen works well or a kennel. I DO NOT recommend leaving your puppy in a small plastic crate 8-9 hours while you go to work, the puppy has nothing to do and is very board. If you work, leave the baby in a playpen or exercise pen. The above examples are available at www.petedge.com.