My new doormat is 3.9 square feet.
Yes, I did measure it specifically to use to illustrate how small 4 square feet is.
10 square feet is *exactly* the size of a standard fiberglass bath/shower insert of the sort that goes into a new house's second/guest bathroom.
4x4 = 16 square feet = 4 chickens for the coop.
4x6 = 24 square feet = 2.4 chickens in the run.
4 chickens need 40 square feet in the run -- twice what you have. Expanding wider is better than a long, skinny run. If you can make it 6x8 or even 8x8 it would be more versatile and useful than...
The Usual Guidelines say that each adult, standard-sized hen needs:
4 square feet in the coop,
10 square feet in the run,
1 linear foot of roost,
1/4 of a nest box,
and 1 square foot of permanent, 24/7/365 ventilation -- preferably located over the birds' heads when they're sitting on their...