It means they are probably covered with piss because he hasn't changed the bedding.

All puppies do, every few minutes, all-day / everyday, is piss and shit in their whelping box. Even when mama tries to clean them, it doesn't take long for the pups (and mama) to start losing hair & get scabs/sores all over themselves.

The solution would be to remove the bedding, clean the whelping box ... bathe the pups & mama ... and repeat this process every 2-3 days.