This happened to me last summer and the exact same situation is unfolding again, same 2 hens. It was terrible, my silkie goes broody (as she does) and it's easier to just give her a few eggs to hatch than try to break her. So she's been sitting on 3 eggs for 2 weeks, now Lois comes along and decides she wants to hatch eggs too. Silkie is tiny and Lois is a big hen. They brood together in the same nest just fine. But once the chicks hatch it just breaks my heart. They fight like crazy over the chicks, and poor little silkie lady is just no match for big Lois. Eventually little lady has to give up, but not before Lois beats the shit out of her, and the chicks are all upset and scared, it's just the worst. I have tried to break broody hens before, but my girls are really determined. I think I'll separate Lois before the chicks hatch this time, as little silkie is my favourite and I just can't let Lois do her like that. It's a complicated situation in my experience to say the least!