
Well that sounds like a true breach, but even if born without this you can loose them.
I find some bitches are so intent on cleaning they make access to the teats very hard. I would let her clan them up and then roll her over onto her side to expose all one row of teats,a and then also make sure that she uses the other side if she has a preference for lying one side.
My Lexi was the opposite she was always almost belly up so pups could get o all 10 teats. It made it hard to get any of those nice Mum and pup pictures. Her Mum on the other hand was not one that made things especially easy for the puppies, she was a washer.
Another reason some bitches don't roll over is they are a bit tense and worried so they don't relax enough to roll over.
With mien I find that after four days the pups are big and mobile enough and Mum careful enough to get past the crushing risk. Crush bars are only a help with pups at the side of the whelping box, not when she flops on one in the middle. Though they are not a heavy or clumsy breed, I did loose a pup that way on the first night after a long labour.