I currently have just 6 hens in a chicken tractor. Well I've got 6 chicks that will be placed in there about June or July. What I have now is just 4'x8'x4'. The new one that I have designed is 8ft wide X 12ft. long X 4ft. tall. Do y'all think that it will be large enough for the 12 hens once I add the other 6? Is 3 nest boxes enough or will I need 4? The coop itself will be 3ft high 3ft deep and 8ft wide. Half of it will be roosting area. Is the room that I'm allotting enough for then? Should I make it stationary or mobile? Thanks in advance.