I have three 8'x8' pens in my breeder barn. I have one cock and five hens in my "A" team pen and one cock and four hens in my "B" team pen. I have two back-up cocks in a small pen and about six back-up hens in my egg flock. I use the third pen for a pair of nice RIRs that are trying to talk me into breeding them. All the other pens are used for chicks, juveniles, segregation, etc., as needed. I rotate letting the breeders out to free range so they usually spend all day out every other day.
I do not tolerate a mean rooster on my place. In all the Silver Campine roosters that I have raised, I have only had one that followed me and looked like he was thinking about rushing me. He never did. He did, however, chase my 12lb house dog around the yard several times. He stayed for a while, but didn't make the final cut. Pity, he was feisty.
I have two pens that are 4'x8'x4' with half covered and walled and the other half wired. I cut holes in the plywood walls and slide a 2x4 through so that a couple of feet stick out on both sides. I then hook a strap onto the ends and hook the strap over the teeth on the bucket of the tractor and pick it up to move it. Its best if someone walks along to steady it, but I CAN do it alone if I have to.
Here is my 8' x 10' walk in tractors.
The inside of an old 54" x 10' tractor that I took the top off and installed a gable roof. Note the ventilation at the top and bottom. The gable was a large improvement over the flat roof. The flat roof was a mistake that I regretted.
Another improvement that I made to this small "tractor", was a hinged door on the back. This allows me to pick birds off of the roost at night to inspect etc.