I made mine a nice coop and they refused to use it. lol. I gave them about a month to try but they just didn't like it. I felt bad about them getting rained on one night so I put a dog house in the run, put some hay in it and they took right to it. I eventually took the coop out and now I use it for other chickens. Mine all free range during the day and I have not had many problems at all.
My guineas are housed with my chickens. They both have a large covered outside yard too. Everyone free ranges during the day and (thanks to many weeks of training) everyone comes in at night. Guineas need the same type of housing that chicken do.