I am no dog expert, but I agree with PirateGirl.
I have two pits and my first farm. The first girl was ALWAYS gentle! Played but never pawed or pounced. Was in mommy mode since birth! Now the new little girl is a much bigger ball off adhd energy. Instead of trying to teach the dog that what it is doing instinctively is bad, encourage it.
Let me explain.
When she chases the chickens I say you chasing chickies ( or other animal ) High happy excited followed with a more rooted deeper EAAASSSY. The change in tone but allowing to play keeps her cautious.
After a while she now chases the mean roosters into the back to save the porch hens, "Chase the roo, Chase him back" Next she learned to separate the Malard gang from the mated pair. As she learned "Nooo" as the warning shot like I know your thinking it but dont. "Nooo Chasing" and if she moves or tightens I give a sharp "HEY" to grab the attention and let her know Im now mad she over stepped. However the moment she responds well or returns its all praise and excitement. This sets the boundaries but maintains the dogs trust. Prolonged frustration only confuses them and makes them nervous anytime you get frustrated or flustered. That will also cause them to run or act out and do what you don't want. Just the same as to many treats and they will walk all over you.
Recently I have her sniffing out the quail that got out. I thought she would eat it for sure if she got it, but she sees me catching the chikens and birds. Instead of using her teeth ( I tell her no teeth since any time ever she uses them on anything other than a chew toy) she slightly opened her mouth covered her lips and gently held the quail in place until I recovered him. I was amazed! She has no formal training but can basic track and find escaped babies just because I encouraged her natural behaviors and set boundaries within them so she still has fun.
She is only 5 months old. Still a rambunctious teen puppy but they follow your lead!
STAY CALM, be clear with your voice about your emotions, and be CONSISTENT! ( use same words, pitches, responses )
One more idea, be a momma with a puppy. Hold the chicken, introduce to the dog let him smell and set physical boundaries with any pawing or mouthing. They will understand as thats what momma dogs do to nosey teen pups.
Again I know nothing. My experience is from having dogs my entire life. I have learned so much more from having my own two and now a new 2wk old litter!
Good luck! I am sure you will be fine
