Greetings from Kansas and
! Great to have you aboard but sorry to hear about your situation. I obviously don't know the law in your area but it would seem that if you are zoned for ag, your neighbors will just have to deal with it. Have they complained to you or to the authorities or are you just now hearing about it? Do some investigating at your courthouse - just because they are complaining doesn't mean they are in the right. They might just be trying to intimidate you. I think you should also post in the link below for some advice.
https://www.backyardchickens.com/f/37/local-chicken-laws-ordinances-and-how-to-change-them
Also, post in your state's thread in the link below - maybe others have dealt with something similar.
https://www.backyardchickens.com/f/26/where-am-i-where-are-you