
Until the eyes are open and use a baby monitor, especially in large or heavy breds with a large litter.
I had a puppy crushed by Mum in the night at a day old because she was simply exhausted as was I from not sleeping two nights in a row.
She had previously been so careful with her first litter of 9 (she had 6 this time), that I had never even considered it a possibility. This breed is generally not clumsy and are very natural mothers but accidents can still happen, even pig rails wouldn't ahve helped in this case as the pup was in the middle of the whelping box.