I have 30 in an 8 x 16 coop with a 16x20 run and they get to free-range when I am out there with them.
You probably won't need to clip their wings, depending on what breeds they are and how tall the fencing is. If you are mostly free-ranging, wing clipping shouldn't really be an issue.
Chickens don't need to be groomed, they take care of that theirself. (unless you are showing them)
Lots of trees are good for shade and hiding from sky preditors. Bushes are useful for this also.
I work full time, so my eggs only get collected once a day.
Have fun!
