I don't think you would have to frame the walls entirely. Most of the framing against stuff like concrete involves ceiling to floor pieces with top/bottom and sometimes middle bracing. I was thinking more along the lines of a couple of vertical supports ceiling to floor in the middle of the room.
View attachment 3504953
Like this middle post: attached to roof support (if there is one) and rooted in the floor. If there isn't a roof support then maybe a 3-way frame (triangle) of 3 posts, connected at the top, middle, and low to the ground (still root the bottom). Just the framework could create roosts, but could also be used to create some visual blockers
View attachment 3504952Secondary view with roof beams. Walls and roof here are sheets of metal.
Sturdy verticals (whether planed wood or tree trunks/branches) reaching floor to ceiling would give you multiple places to mount horizontal roost places and/or sheets, tarps, wallboard, or other sight blocking obstacles. The wall framing here is mostly non-existent: corners and middle of long wall. The pieces used here are substantially larger than in the house due to greater length spanned/different materials for walls, building codes, and purpose of final project. Hoping it gives you more ideas.
View attachment 3504975Noisy Nox
BTW, wallboard/plasterboard are typically British English terms for the same sort of thing as sheet rock/plywood. Same concept.