I assume, by the puppy boxes you mean whelping boxes ---- growing pups can get out of these really easily if you intend to use them to keep them safe. Depends on what you want to use the crate for. Mine were used if I had to pop out for a short while, to give them some quiet time (and me

) with a chew, or if am doing something upstairs, plus they always slept in the crate at night. Now mine are adults and its stil lthere as they like to snuggle up inside it as its cosy in there (has a blanket over three of the sides, with enough space for air to flow through.