My modenas live in my chicken house. The pigeons have nests/perches high up on the wall that most of the chickens never fly up to (there are occasional ones that will fly up there and lay). The only issue I had with any of the pigeons being harmed was one baby one time that fell out of the nest too early and got beat up by some other bird, don't know who/what (it recovered and was fine though). I think part of the issue there was that I don't think at that time that I had a good "wall" on the edge of the nest box, the front was open, I later put a board on that added protection in that respect.
In general though, the pigeons and chickens (and everything else) get along alright. The pigeons will stay out of the way of bigger birds and stuff.
The modenas are free flighted, when I open the chicken house in the morning, the pigeons are free to come and go as they please, and they come back in at bedtime.