Our chickens and turkeys share space (I don't advocate this, just do it out of necessity). We have 2 coops each 14 x 24, Between the two coops is a 10 x 14 pen open to both coops, and on the far end of one coop is another 10 x 14 coop. Inside each coop are multiple roosts at all heights, and multiple rooms. When we open it all up, the birds can go wherever they want. The breeding tom and hens have staked a territory. They will walk around and look, but they come back to the same roost at night.My turkey pen is roughly about that size and I house 8 turkeys in it, 2 Toms and 6 hens. Im sure it would hold more but I like to give them space especially since during mating season the hens need to be able to flee from the Toms if they need to and the Toms need space from each other especially since they spar often.
By the time early November comes around, we usually have 100-150 hens and about 35 turkeys in this space. The toms usually take it outside 1:1 and only strut indoors. After Thanksgiving it looks deserted, and we shut down one coop in the coldest part of winter to conserve heat.
The combined space is about 24 x 40, about the size of a 3 car garage. Interior height at peak is about 9' and sidewalls are 5'