We have 2 border collies, and just let them sniff the chicks, then we held and pet the chicks in front of them.
If they started licking their chops, we said "NO, mamas birdies" and cuddled the chicks. By the time they were
ready to free range (3 months), the dogs were used to them and considered them part of the family they protect.
I held them in front of the dogs 2-3 times a week, worked like a charm.
ALSO, we keep a light on the coop at night, it discourages predators, and even though there are coons, skunks,
coyotes, cats & dogs around, we've never had a problem. We use a flourescent light bulb in an outdoor safe
floodlight holder. Most of the birds nest at night on the fence in FRONT of the coop, or in the tree hanging above
the coop, and no problems with critters getting at them.
Good luck!