Well, I don't agree with chaining. The only instances I've ever had with chained dogs is that they became territorial and aggressive. One neighbor kept their german shepherd chained to the inside of the garage, but could reach the grass to potty, and it had shelter food and water in the garage. He was very territorial and would only become friendly once he was used to you. He ended up biting the mail man and needing to be put to sleep or they would be sued.

My husband's old neighbor keeps their dog on a chain. I feel so bad for this thing... they do not care for him at all. He walks in his own feces which they never pick up. Well, the dog never used to be aggressive, but one day I was walking up their shared driveway (The dog used to be able to get somewhat in the driveway), and there was a car in the way. I went around it and the dog lunged and snapped at me. He caught my jeans with his tooth and left me a nice red mark with some ripped jeans. I was severely p*ssed off. Haha But now, the poor dog lunges and barks at everything that moves. And, something happened to the poor dog, and his little tail is missing the end now. They're horrible owners, and not so nice people. :-/

It does seem that your dogs are happy and healthy. They definitely look like they love you so you're doin' something right.