Before I got my chickens I studied up on the internet. I read all kinds of information on the Backyard Chicken forum website. It was important to me that the chickens stay in their fence so my dogs or other predators wouldn't get them. I read that a foot feet high fence usually does the trick but some people's chickens escaped. I thought 4 feet would be fine. I was wrong. I didn't have just a few of them escaping. They all did. At first it wasn't a big problem because their smaller fence is within a larger fence and often they'd just be wandering around the goat's fence. It wasn't long though till they flew out of the bigger one too. One night we didn't get home till after dark and when I went to close up their pen and make sure they were in bed, I found 4 of them perched on the goat's gate and one missing altogether. We looked around with a flashlight but couldn't find her. I got up early the next morning and found her perched on a 2X4 of the new barn. She flew down and I had to catch her and put her back in the fence because she couldn't find her way back in.
We decided it was time to clip one of their wings. We had friends visiting this weekend so they helped. James and Mike chased and caught the chickens and I did the clipping. I wish I thought earlier to get the camera because watching them catch 11 chickens would have been a great video. I've told you my chickens aren't too smart but they outsmarted James and Mike several times. It was a sight to be seen. Four hours later there were 5 chickens walking in our driveway. Ugh! We cut their wings shorter. As of yesterday there have been no more escapees but I'm not holding my breath.
We'll have to do this regularly because they molt and grow back their flight feathers. We're still having fun with them.
I'm downloading a video right now of James catching one of the chickens and me clipping it's wings. It's not near as funny as when they caught the chickens the first time but you'll get a picture of how hard it is to catch a chicken. It takes about an hour to download so if the video isn't on here check back later.