Stillborn fully formed rabbit kits

by Sarah
(Australia)

Hello!
My half Netherland dwarf had three little babies this afternoon, I think I saw them within half an hour of them being born. Unfortunately two were dead, they were fully formed however one was extremely skinny, and both looked like Mummy bunny had bitten at their bellies. Both of their eyes were open.

What do you think this could be the cause of?
The third little bunny has a huge round belly and full of movement, and I have seen Mum feed her already.

I mated Mummy bunny with another half Netherland male.