I was out in the garden and I noticed a hen on the wrong side of the gate. I went back through the house and walked round to where she was standing with a bit of weed in her beak. She even managed to look guilty just before she went back in the garden. Where the gate is there is a little bit of a drop at the edge of the concrete path where there are stones. At that point she can get under the gate. Her exit has now been blocked and I will be getting a wooden gate that doesn't have that gap at the bottom.