For co broodies just be sure the hens don't see each other as a threat. I had a friend who had one broodies kill all the chicks of the other. The aggressor was so aggressive they had to rehome the second bird.
My broodies puff up and yell at each other but a lot prefer to have a friend to raise babies with. My silkies will break off into packs of 2 or 3 when the chicks areclose to the same age. When ione mother quits the rest will take over until the last mother standing has all the chicks.
I have 2 marans co brooding on the porch right now!
Mine are in separate boxes but fairly close together and so far I haven't seen any animosity between the two. The idea of them raising chicks together is too cute
