I would keep the top of the roosting bar about 10 to 12 in from the top of your poop board. Not the lip.I’m so confused now. What? Drafts are bad. We always hear that. Drafts are bad. Ventilation is good. I feel like having a draft come up from under their roost is not good.
Because of my not stellar construction skills, there are also drafts coming in through the front door. I guess I’m not as worried about that because it’s on the opposite side of the roost.
I will definitely look up what you mentioned about the eaves. I like the idea of not using hay. It did get messy. I will lower the roosting bar. How much do you think?
You are thinking about drafts in mammalian terms not avian. As long as any gentle breezes or drafts that pass through roost space do not open their outer feathers that is fine. Their feathers getting blown open is what allows their heat to escape.
For me, the best way to achieve low fresh air intake is to leave my pop door open because I have a fully predator proof run attached to my coop. That also enables the birds to immediately go outside when they come off the roost in the morning so I don't have to clean my coop more than once or twice a year.
The other way you could achieve this is to cut holes or remove the bottom 2-3" of siding between the studs in strategic locations and cover them with hardware cloth.
As most of the ventilation will be overhead, that is where you need to be concerned with cross drafts hitting the birds in the head or the body. Hence the utilization of baffles to redirect that air flow.
