I have seen a number of newbies and oldies asking for tips on predator proofing a pen. I have attached some pics here to show you how we have done it... As you see the run only used when Im not home during the day and Im not home other wise at nite they are locked up and during the day are free ranging but I am next to a woods and they have thickets etc to hide in... Electric wire covers the perimeter around the coop and pen Ive been pretty successful at keeping critters out my coop alone should do it but the electric wire is insurance... Also and I know it goes into the other section but check out my waterer 15 gallon automatic..... Anyway the top is deer netting and only to stop birds... Now if the birds are outside I disconett the fence my charget has killed a small rabbit a small coon and numerous small sparrows... It is a weed cutter but to protect the birds Ill use it... I included a pic of the inside as you can see very sturdy and the windows are 3/8 inch lexan un breakable no coon to push em our... Any comments or ideas are welcome...