Best Fence for Chickens

I have a 4x8 foot coop and a 10x16 ish foot enclosure for my chickens. I had let them out daily in my 1/4 - 1/2 acre 4" chain link fenced back yard. My old girls have been content with this for 4-5 years. I got new chicks last spring and they've not been content with this arrangement. They'd hop over the front fence and hang in my next door neighbor's yard - who didn't mind, so I didn't need to do anything. However, they decided that wasn't good enough and have decided they want to hang across the road in another neighbor's yard, which isn't ok and has caused concern of those driving on the road. This is a suburban neighborhood.

I'm thinking of putting up another fence in my yard to contain them to a smaller section of the yard, this area would not have anything over it like their enclosure. How high does the fence have to be to keep these new chicks in? The new chicks are a speckled sussex, a golden comet, a buckeye, and a a rhode island red.

Any thoughts or suggestions on fence style? Cheap and easy are always a bonus. I'd tried 4 foot plastic fencing with those metal stakes, but the young girls just hopped over.

My husband thinks that putting a fence in the yard will look stupid, so I'm looking for something that will look awesome. Not having poop on the patio will be a big selling point though.

Someone on here has a good fencing method for discouraging flying over. If I remember right, it's a normal height fence, but it is topped with an extension of poles + deer netting to raise it to 7' or so. No top rail on the deer fencing part...takes advantage of a chicken's reluctance to fly over what it can't properly see the tip of. And unless there was snow, the deer netting was fairly "invisible" except for the poles holding it up.

You may do a search on the site using some keywords from my rough explanation to find the exact thread.

Alternatively, you could clip their flight feathers every so often.