My back yard is fenced in, and my girls will have a small run under and around their coop. But I'm thinking I will set up an area with temporary fencing, that I can move around as necessary. Step-in posts, flexible plastic fencing, as high as I can get it. I know they might be able to fly over the top, but will they be likely to scoot out UNDER the fence? I'm new to this, I'll be getting my chicks (3) in late April. I've read tons about chicken care, but don't know what to expect as far as behavior. Thanks.