Coop size question

[domromer]

I plan on building a triangle shaped tractor with one end of the tractor being thier coop at night. What size does the coop need to be for 6 barred rocks? I now the rule is 4sqft per hen, so 16sqft, but is that the same if it will only be there house at night? Otherwise they will be in the tractor during the day. I'm trying to build something that has enough room but can still be moved.

 

[CoyoteMagic]

I think I've read some place that their outside space should be like a minimum of 6ft per standerd sized chicken. tractor has to be at least 6ft wide X 6ft long for that many birds