Good examples of skirt/apron installation, tho I'd not recommend 1/2" HC...go with 14ga 1x2 or 1x1, will hold up much longer and is easier to lay flat.Welded wire fence with 1x2 or 1x1 openings. If you have weasels then you would need 1/2 hardware cloth. For diggers 1x2 is great for a skirt.
JT
http://www.backyardchickens.com/t/1110498/wire-around-coop#post_17093528
https://www.backyardchickens.com/threads/new-coop-project.1169916/page-2#post-18481208
Oops I see you already have an apron.
200 lbs of feed for 3 birds?