swimM4r - Is your dog a herding breed? (looks like it from your profile pic) They're so smart, I think they understand the chickens are now part of the family and are to be protected. You might just want to keep an eye on the intense focused staring, that's what my dog would do before he would snap at them. I would correct him when I saw that look, and reward whenever he would just lay next to them and relax. You just have to be able to read your dog. But it does sound pretty promising if he's been around them so much without making a move.
Here's a picture of Smokey when he was aggressive toward the chicks. You can see the intense stare.

Here he is after just a few short training sessions. He really watches over them and tries to keep them all together if he sees some wandering. He takes his job very seriously!

Here's a picture of Smokey when he was aggressive toward the chicks. You can see the intense stare.
Here he is after just a few short training sessions. He really watches over them and tries to keep them all together if he sees some wandering. He takes his job very seriously!