My male doxie (now 3 1/2 years old) went nuts over the chicks last summer. He stalked the coop, he stalked the chickens, he ran circles around them wherever they were. I didn't think I would ever be able to trust him with them. Then when they were about 3 months old, he sneaked out and 3 of them (a GLW, a Welsumer, and a Delaware) cornered him in the garden, and at least one of them pecked him pretty good. He is extremely submissive to all the chickens now. Tail down, head down, slinks to the house. They have a mutual understanding about ignoring each other.
My female doxie (about 3, but I've only had her since February) is going through the same thing with the new chicks. The difference is that she actually attacked my EE at one point. There were feathers everywhere. Lily lost butt feathers, a wing feather or two, and a ring of feathers around her neck. I got there just in time to pull her off. I'm not sure she will ever be trusted around the girls, but she isn't crazy about being outside, so it may not be an issue. I keep her in when they are out of their pen in the yard, and if she needs to go out, she goes out on a leash.
My female doxie (about 3, but I've only had her since February) is going through the same thing with the new chicks. The difference is that she actually attacked my EE at one point. There were feathers everywhere. Lily lost butt feathers, a wing feather or two, and a ring of feathers around her neck. I got there just in time to pull her off. I'm not sure she will ever be trusted around the girls, but she isn't crazy about being outside, so it may not be an issue. I keep her in when they are out of their pen in the yard, and if she needs to go out, she goes out on a leash.