As everyone else has said, it depends entirely upon the dog. My own dog was never a problem with my chickens, but he was trained from day one when we got him at 7 weeks old. However, when my son comes to visit and brings his Golden Retriever, my chickens stay locked up in their coop/run. I don't trust any visiting dogs except my mom's dog. I've been dog-sitting her for the past few days and she is not a problem either. They squawk and run and she just minds her own business. Are your neighbors' dogs in close proximity to your chickens? (Had to ask, as where I live, "neighbor" could be anyone in a 10-mile radius) If so, I would suggest building them a sturdy run attached to your coop - you can leave them there for awhile anyway and see how the dogs react to the chickens. How about putting up a fence between you and the neighbors. Is that an option? Do the dogs frequently visit your yard? If so, you could talk to the neighbors about keeping them home, or start training the dogs when they come to visit. I would certainly not leave the chickens loose unattended until I knew how these dogs were going to react toward them. And even then, I'm not sure I'd trust them completely.