achick:
10'X50' is a good sized run! I doubt you will have problems. Mine used to free-range, but after the neighbor's dog killed one of my hens, I am confining them to a much smaller run while I'm arranging for a much larger, secure run to be completed. I thought there would be a lot of issues with them in the small run, but there really have not been many. The run is portable so the change of scenery helps, though with all this yucky weather, I have not been able to move it around much. They seem to be entertained with all the perches, hanging treats, hay, kitchen scraps and the flock block, and if the weather is tolerable, I do let them free-range while I'm working in the yard nearby. I always leave a couiple of birds in the run so the others don't wander far, and are easy enough to get back in by dropping a persimmon inside the run.