My Grand Plan...

[Ol Grey Mare]

A good rule of thumb....if 5he coop list its dimensions in inches skip it. That is your 1st sign that a) the producer has no idea what they are doing and what it takes to house poultry and b) you and your flock will be very unhappy in the long run

 

[sphillips]

Noted. Ok, but, I found Bantam White Leghorns today. I would love to have some of these. Surely, this coop would hold 10 bantams comfortably? How many bantams? 8? Based on 4 regular size chickens?

 

[aart]

Noted. Ok, but, I found Bantam White Leghorns today. I would love to have some of these. Surely, this coop would hold 10 bantams comfortably? How many bantams? 8? Based on 4 regular size chickens?

It's more than just size that is 'bad' about these tiny kit coops.
Flimsy material, no ventilation, lousy (low) roost locations.

Maybe reading a few of these will convince you to build your own:
https://www.backyardchickens.com/search/19628243/?q=prefab+coops&t=post&o=relevance&c[title_only]=1

If not, here my favorite prefab modification:
http://www.backyardchickens.com/t/1134399/help-hens-roosting-in-nest-boxes/10#post_17749535

Or do both....
buy the prefab for the bantams,
then after you have it for awhile,
you'll build a big coop for some LF.

 

[BobletFarmBirds]

Definitely get them in the 8x8 before they are full grown.
I would recommend Easter Eggers. I have Olive Eggers and Black Copper Marans, and they seem to do okay in the heat.