Brahma Size - help please (time sensitive)

[CamarilloChica]

Hey all - a little advice please! I'm building a door to my coop as my 6 week old brahmas desperately need to go outside. I want to make the door as small as possible so it is insulated, but obviously not too small as brahmas get pretty large. Could anyone please provide the measurements of their adult female brahmas or suggest a size for the door?

Thank you all!

 

[ChickensAreSweet]

I would look to see how large the automatic coop doors are just in case you ever want one and adjust your size accordingly.