Folks, if this is *literally* 1/4 acre (100x100' or the equivalent), that is going to be quite expensive to cover with even just a netting top, especially if snowload is ever a consideration.
Pat
Well, it was apparently HIS choice to fence in that large of an area without consulting your preferences first...
Seriously. There is no big problem. Essentially you will have chickens "not quite free-ranging", or anyhow loose in a very very big pen. There is nothing wrong with that. The...
Well it'd be a gigantic project to PUT a top on a 1/4 acre area ANYhow
Without it, yes there is the possibility of hawk attack, that's just the way it goes. Provide cover objects the chickens can duck under if they sense a hawk heading towards them (picnic table, bushes, brush piles, etc), and...