Chicken Coop Door Large enough?

[Hal9000]

I have two month old Orphingtons and Australorps. Would a 9 inch wide 15 inch Tall opening work for them to come in and out of the Coop? I am afraid that the width is too small.

 

[Hokum Coco]

I have two month old Orphingtons and Australorps. Would a 9 inch wide 15 inch Tall opening work for them to come in and out of the Coop? I am afraid that the width is too small.

My pop door is 9x12 and this Delaware rooster get through no problem. Wish I had of cut the door about 12 inches off the floor especially in winter with deep and frozen litter. Roosters weighing 8.5 pounds (3.9 kilos) and hens 6.5 pounds (3 kilos), the Delaware is a medium sized breed.