Good question. I assume you want both of them to hatch?
You don't get any guarantees as to what will happen with chickens and behaviors. Over the years I've seen many posts and even photos on here of people with multiple broodies in the same coop and with each having their own nest in a bank of nests. I remember one photo where someone had 7 different broodies, each broody on her own nest. I've seen plenty where two or more broodies share a nest and work together to hatch and raise the chicks. There are several posts on here about how cute two hens working together can be.
But there have also been some disasters. Sometimes two broodies fight over the chicks or eggs with chicks or eggs getting damaged. I had that happen once when a hen that had just gone broody tried to take over a nest where the eggs had started internal pipping. A lot of the time when the broody hens fight the eggs or chicks don't get damaged but one just takes over. If a hen hears eggs pipping she might abandon her nest and go join the other hen to help her raise the chicks, no fighting. Some people that have two broodies share a nest say that one broody might kill the chicks that hatch under the other. I have not seen that. I'm sure there are other things that could happen, either good or bad.
From my experience and from what I've seen on the forum most of the time two broodies can have nests in the same general area or even share a nest and it works out great. But occasionally there are disasters. I tend to break a second broody but that's because of the way I raise them, I don't want a lot of chicks of the same age, preferring to spread them out because of limited freezer space. If you wish you can let them interact when broody, it will probably work out. But there are risks. It would probably be safer if you can separate them.
