4 sqft is only night space and does not cover outside run or free ranging. They need indoor space for inclimate weather. Runs are not included in coop space.
Most of the prefab coops are poorly designed. I'm having a wood shed dropped off that I can modify myself. Nesting boxes shouldn't be on the floor. There should be no roosts or access over the nesting boxes for chickens to poop down on them. Proper sanitation is key. You can't do deep litter...