Mothers do kill pups at times. In general hot or DA females are normal mothers. Bad, pup aggressive, or mothers that kill their pups for other reasons can happen in any breed.
A DA female still has maternal instincts. There are dogs which are very hot towards other dogs but might be ok around a pup (im talking 8 week old pup that isn't its own).
Some are bad mothers, they seem to have a hormone issue. No maternal instincts what so ever. It's like they don't realize they are a mother. They won't feed the pups, injure/mutilate them not out of viciousness but because they don't know what they are doing. They might behave very stressed out.
Some are not right and will kill their pups everytime. But those are not the norm.
There are also times when something is wrong with the pups. Mothers will often abandon such pups, others might kill them. I have a female which is a great mother, she has also nursed pups from 2 other females, doing great. But yet another time it didn't work out well. The mother of the litter was ignoring them basically, when I gave them to my other female she ate them. I assume they had a problem, animals know when young are inferior.
I've a very hot and serious bitch. She was a great mother. Every dog I have of that line is. Another will kill other females pups, she is intolerant of other dogs, even young pups. She's a daughter to the female which ate the pups I spoke of above. By contrast with her own pups she is a good mom, night and day in her behavior.
