My dog is great with chickens.
When I got him he was a rescue dog- a mystery dog that was a stray so we have no way of knowing what he actually is. Well when we brought him home he grabbed my cat by his neck and shook him! It wasn't a KILL shake - more of an "i'm scared of everything and want you to know who is boss" shake. well we right away yelled "NO!!!" at him. he only tried it one other time since then a few days later and we said "NO!!!!!" in that dominant, loud, booming low voice again. he never tried it after that. he was just too scared to try.
when i hatched out my chicks in may, and they started peeping and being talkative... my dog wanted to chew on them! squeaky toys!!!! - yeah.... well I had to figure something out. he already associated the word chicken with getting a treat. because i give him chicken treats... so hmmm. I decided to call them "babies". I would take a chick in my hand and say "see the baby???" and when he got excited I would say "Be nice to the baby..." in the low *boss* voice and he would come over and sniff and if he got too interested, perked his ears or put his mouth near my hand i would say "You be nice..." in the same somber tone. he knows that voice is the DO NOT CROSS THE LINE voice. I did this repeatedly until he knew they were off limits. every day, and every time i was near the chicks it was the same thing. he was never allowed to be with them alone. ever.
my chickens are now 19 months old. when they were about 9 weeks, maybe even younger, my wyandotte roo pecked his nose. he didnt like it! it scared him. he stays a good distance after that. I dont think he expected it. after that i decided to socialize them with him even more. i would randomly pick up one of my chickens and make himsit or lay down and then put the chicken on his head, back, or next to him... being careful, in case he decided to "play".
at this point, he is so used to them that now he will shuffle around in the yard playing with them. i have one hen that will charge at him and he jumps backwards excitedly. then he'll shuffle around and "rarf" at her and she'll turn her head sideways and run towards him again. whenever he shuffles around, she jumps sideways. and when he stops shuffling, she charges him again! it is so funny.
i have a pic of him on my byc page. i think he is either a poodle/spaniel mix or a spanish water dog.