EverythingDucks
🙄🤚 𝙻𝚒𝚝𝚝𝚕𝚎 𝙳𝚞𝚌𝚔
I'm to lazy to write this from scratch again so I found where I've said the same things 

Pictures!!!!
I really recommend Zak George's Dog Training Revolution. He has tons of videos and a great book for puppy training, fixing behavioral issues, and tons if fun tricks. Though I don't think he has a video about this he covers a lot if other very useful things.
Be sure to teach her leave it. This is one if the most important thing to teach a puppy. To do this, set a treat on the ground. Keep your foot near. If course she is going to go for the treat, so when she does just put your foot over it and say "leave it". Then reward her with a (different) high value treat. Boiled chicken works great.
Do this a couple times a day. Keep it short and fun. Start with 5 minute training sessions. You could do three a day.
Never ever use leave it in something you instead for her to have afterwards. Some people tell their dog to leave their food while they put it down. Do not do this. This will teach her that she is supposed to eat what you tell her to leave. Imagine you drop a pill on the floor and tell her leave it. It is very important for her own safety that she does not eat that. Or with chickens.
When you are training her do it in a voice that you would use in those situations. While I recommend using a happy voice for most other things to make it more fun, in this case you want her to be used to the voice that you would use in real situations.
The best way to fix issues is by preventing them. Always keep her on a leash when outside by the chickens. If you notice her looking at them a lot redirect her. It's normal for puppies to be curious about new things but if they become too interested they may chase after them. Tell her to leave it and teach her to look at you (Zak George has a video on this). Use this whenever you see her staring at the chickens. And reward her a bunch. Use high value treats for this. If she is toy motivated, use her favorite toy instead of treats.
You want her to ignore them completely. Reward her when she does so and redirect her when she doesn't.
Some people use clickers to signal that they like what their dig is doing then reward them, but IMO carrying around a clicker all the time isn't very practical. Instead say "yes" . I prefer "yes" over "good girl" because often times people will say good girl or boy when meeting or petting a dog. And usually the dog will he excited and probably jump up and bark a lot. That is not something you really want to reward them for. Then they'll think you want them to jump and bark. So instead, "yes" is a much better option.
Sorry for such a long post but I hope this helps! Good luck!