Pop door size?

[gabby3535]

Can anyone make recommendations for the correct size pop door for HUGE light Sussex?
Is 18 x 18 inches too small, too big, or just right?
These chickens (although just babies at this point) will apparently be HUGE when full-grown!!!
Thanks!

 

[Zahboo]

that should be fine.

 

[Mahonri]

I have some big chickens and they go through a 14 X 14 just fine.

 

[cmom]

I think my pop doors are around 14 x 14 inches There are pictures on my BYC Page..