Question about chicken's run

[BrentonL]

I am new to building anything to do with chickens. I have some experience watching over chickens for a few families that go out of town regularly. They have 3 chickens in a pen that seems kind of small. When they first built the pen, the grass in their run was very lush. Now there is nothing but dirt and mud in their pen. In looking thru posts about runs here, all the runs still have grass growing in them. Is there some trick to making grass grow, or are their pens barren because the run is too small?

I plan on buying a dog kennel from TSC and using it for the pen to make it a 20' by 20' square. If I have 8 chickens, will this be plenty of run space for them?

Thanks!
BrentonL

 

[ChicknCommander]

The bigger the run the harder it would be for the chickens to mow the grass down