I think that is a great idea. I thought the same thing with my full size mattress as they were all laying on it. Its got more cushion then dog beds. If he grows out of the crib mattress move on to a twin.
Actually, I am stealing this idea for my parents senior girls. My mom would like the idea of being able to easily wash the fitted sheets. I will buy several sets. The girls would be comfy too. Thanks for posting this
That's what we do! In our area the nice water 'resistant' crib mattresses pop up on Craigslist for a few bucks or free all the time. Hard to explain a single grown man washing a load of crib-sized fitted sheets at the laundromat, but hey... it's worth it in cost savings over $50 dog beds!