Chicken Head Height and Roost bar to ventilaion

[Doc7]

Here is an older photo from construction but on the long walls of my coop you can see the tall wall has a ventilation window, as does the short wall which also has a nest box cutout below It.

If I draw a straight line from the bottom of the “low wall window” (which I’ve actually blocked some of with a board so that it isn’t quite as low) to the bottom of the “high wall window”, how far below that line (presumably the “draft line”) should the roost be? I assume the draft line should be a little higher than the chickens’ heads, so I need to place roost at optimal height above the nest box but with their heads below the draft.

My breeds are hatchery Buff Orpington, Plymouth rocks, Delaware, Easter Egger, and New Hampshire red.

Thank you!

 

[aart]

so I need to place roost at optimal height above the nest box but with their heads below the draft.

I don't think you can....that's the problem with small, short coops.
What are the dimensions of your coop, W x L x H?
How many birds do you have?
If you put the roost the recommended ~12" above nests, looks like their heads will hit the roof. Think you'll just have to put the roost below the 'draft line' and hope they don't sleep in nests.

Determining drafts can be tricky, can depend on prevailing winds.
You may need louvered vent covers in winter.
This discussion might help:
http://www.backyardchickens.com/t/1048597/ventilated-but-free-of-drafts

 

[Doc7]

Sorry but your eye may be off. The coop is 4’ tall and the nest box floor is 12” off the floor. I can place the roost at a minimum 18” height and they have 2.5’ to the roof, a little under 2’ to the bottom of the window cutout. It is 4x6 coop for 6 hens.