This is only my second year keeping turkeys but I have kept them in a coop at night.
Last year we had 2 and they had a 2x6 for a roost, which they liked well. They had about 2 feet or so of roost space each but their coop was fairly small.
I brooded them inside their coop. Once they were allowed out to free range they were fed every night in the coop. Occasionally the hen would try to roost on top of the coop but that was only if I didn't get out there in time to open the door (I kept the door shut since they were in my goat field).
I have 12 turkey poults this year and they are currently brooding in a coop that will go to geese later this year. I plan to build space for the turkeys in my goat barn using the same methodology that I used last year...2-3 feet of roost space and 2x6 for roosts.
I'm not turkey expert by any means but this has worked for me so far. I hope it helps.
Have you used the goat area before for turkeys I think I have seen others say they have done this and for some odd reason there turkeys began to die off?.