I went to Amazon and looked at the coop. First it doesn't give you the full dimensions so you don't know how wide it is or how tall. Second if you read the reviews you will find out that it received very poor reviews.
If you are only going to have 3 chickens just use a dog kennel, line it...
I have 2 size chickens, layers (isa browns aka sex sal link) and mixed bantams, they both free range on the same property. Although they share the same coop they are separated in the coop and have different doors. My problem is I can't keep my layers out of the bantam area, they take over...