~Wind~ :
We have 4 pure labs, 1 lab/border collie ad a yorkie. The funny thing is that the yorkie is the one that we have to watch, she wants their food and will chase them to keep them away from it.
The key is to have a really good "Leave It" response. The once that is good and strong you simply need to say "Leave It" and your good to go.
Now I know thats harder than it sounds. I spent may hours with our dogs working on this. 
Start simple by putting a treat on the floor, say leave it and give them a treat out of your hand right after the drop. Dont even give them a chance to think about what you put on the floor. Then slowly start to space out the treat drop and leave its (drop "Leave it... 5 sec treat". It takes time and patience. But they will slowly learn that Leave It means I ignore what fell cause I want a treat. 
Once you get them ignoring the fallen treat start to challeng them and drop a few treats one at a time. Continuing to say leave it as they fall. If they have an oops then the game is over you say no and then ignore them. Eventually they will clue in that leave it means leave it and it really sucks when they get ignored/kennelled for not listening. 
After some time you space out the leave it command with only treats every other time, the times with out the treats you just pick up the fallen treat. Eventually you will be able to give the command and have the response you want without a treat. 
Then you take it outside, Start back with treats. Slowly start working "Leave It" by the chickens (on a leash for safety for all). When you start working by the chickens make sure you have treats and that your dog is hungry, best time to work is before a meal when their stomaches are ready to nom nom. Keep their attention on you and ignore the chickens yourself. 
Slowly get closer and closer to the chickens ignoring them yourself like its no big deal. Keep the attention on you and the treats.
Once that is going well try walking past a chicken on the leash. Say "Leave It" and keep walking.
It will get there eventually, the key is consistency and knowing that it make take days or even weeks, but be patient and keep at it.
Hope that help.
THank you SO much, this is a big help and Max is already starting to respond to training. He is goofy but pretty smart! Hoping that even though I don't plan on leaving them alone that I will one day not have to be worried aobu tht edog trying to eat the girs!