We have just used a disposable whelping box purchased from Newdog. Complete with rails and non-scratch up fleece bedding. The bedding is excellent as there is no way the bitch can scratch up the bedding; either burying the pups or leaving on them to get cold without a fleece to lie on. We use a microwaveable pad which we slip into the strongly made fleece blanket so that the puppies can cuddle up to the warmth.
Here is the link to their website:-
Newdog
They have sent us some literature so if anyone wants to talk about their system or get some info. you will find us at Bath, Southern Counties and other shows.
Jim and Kath