Good size for bantam condo?

[playswithfowl]

I am going to be downsizing my bantams, and am going to be modifying their coop for more layers, and am going to be building a condo coop for my bantams. I'm going to be keeping 4 bantams in it. I was thinking of having a 8x4 run, with a 4x3 raised coop. They get to run around our yard around a third of an acre maybe a little bit bigger nearly everyday. Do you think this is enough space or more?
Thanks--AJ