I'm not sure if anyone's asked this yet, but do you have these chicks in with the rest of the flock (not just the two mothers)? Everything I've ever read says that you have to separate new mothers and babies from the rest of the flock... the other adults will more than likely kill the babies. I don't think it is as common for the mamas to hurt the babies, though it can happen, and if this is the case, you need to raise the babies yourself indoors with a brooder lamp. But, I would think the first thought here is that the OTHER chickens are picking on the babies... not the mamas.
