Today we went up to the river trail and walked around without a physical leash on. He stayed in a Heel even when dogs were carrying on behind a fence at him. I let him into a free walk so he could sniff and run around and he was very interested in some chickens who were in a yard but as soon as he felt the page (vibration) from the collar he turned right around and came back to me. He pouted a little when we didn't go back to the chickens but he soon got over it and got on with the walk.
He is doing great. He jumps the gun a little with Stay and Come and his owners will be encouraged to practice long Down/Stays with him when he goes home so that he doesn't lose this skill.
As I said, tomorrow we are going out to the farm to get a good walk in the high pasture and work in an environment that is more like home.