Right now I have two guinea hens brooding eggs in the henhouse. The only problem I have is that the chicken hens still want to lay their eggs in the same nests. I won't try to move the guineas until the keets hatch. I just have to try to find the chicken eggs under them every day.
The chickens won't hurt the guinea but may break eggs getting in and out.
I would take the eggs and put them in an incubator or tAke them when they hatch. Guinea hens are awful mothers and will lead keets through dew, rain, and cold mornings. They will likely die if you let her raise them.