Yes, he will almost absolutely go after chickens.
But don't lose hope yet. Although it is very true that bird dogs can be very difficult to train not to chase and kill chickens, this certainly can and has been done. You must be able to let the dog spend time with the birds while separated by a fence or restrained on a comfortable lead. He shouldn't be in any position that he sees as punishment though, such as being confined if he in normally not confined. The dog must be able to see the chickens in their natural routines and not just as caged animals. Correct any attention the dog gives toward them immediately. If he looks at them for any more than a couple of seconds in an alert position (ears and body forward) he must be corrected. He will have to learn to lay submissively as they move about. Any chasing or following must be corrected immediately. Finally, when the dog is able to relax while the chickens are moving about you would try letting them together. It would probably take a lot of time (and I mean weeks or months) and careful attention but I think it is possible.
We successfully reconditioned a wild dog that killed to eat and hunted to survive before we started feeding her. I never had to use any force more than one time in the beginning when she went for the birds and I put her to the ground in staunch disapproval. After that I would just growl or say a sharp "Hey!" if I saw any unwanted attention. Eventually we let the birds free and the dog never harmed them, even when we were not present. I think if a wild dog can be reconditioned, almost any dog can.
But don't lose hope yet. Although it is very true that bird dogs can be very difficult to train not to chase and kill chickens, this certainly can and has been done. You must be able to let the dog spend time with the birds while separated by a fence or restrained on a comfortable lead. He shouldn't be in any position that he sees as punishment though, such as being confined if he in normally not confined. The dog must be able to see the chickens in their natural routines and not just as caged animals. Correct any attention the dog gives toward them immediately. If he looks at them for any more than a couple of seconds in an alert position (ears and body forward) he must be corrected. He will have to learn to lay submissively as they move about. Any chasing or following must be corrected immediately. Finally, when the dog is able to relax while the chickens are moving about you would try letting them together. It would probably take a lot of time (and I mean weeks or months) and careful attention but I think it is possible.
We successfully reconditioned a wild dog that killed to eat and hunted to survive before we started feeding her. I never had to use any force more than one time in the beginning when she went for the birds and I put her to the ground in staunch disapproval. After that I would just growl or say a sharp "Hey!" if I saw any unwanted attention. Eventually we let the birds free and the dog never harmed them, even when we were not present. I think if a wild dog can be reconditioned, almost any dog can.