Oh and thin little bird netting like you can buy at the hardware store isn't going to stop a chicken from getting out (experience there), much less a hawk from getting in. Get aviary netting or something else heavier like this.
http://www.amazon.com/Bestdealdepot...qid=1426282873&sr=8-3&keywords=aviary+netting
http://www.amazon.com/Bestdealdepot...qid=1426282873&sr=8-3&keywords=aviary+netting