IMHO, You need to once again search for your states 'right to farm law.' It will lay out Federal guidlines that were written to stop just this sort of harrasment. Each state has a slightly diferent version to comply with the Federal mandate. Be carefull that they may specify animals in a general way, and place poultry in a diferent meaning. The Federal guidlines are written to include poultry at a rate of 10 chickens per 1 animal unit, and most lands are limited to 499 units before they come under federal eegulations for animal care. (thats 4,999chickens).
The fact of Grandfathering is for 'land use' and not individual animal lives. They should not be able to limit your growing your own food in any significat way. You do not have to 'agree' to subrigate rights you already have.
Read and take the meaning of the 4rth, and 14th Amendment to the constitution. the 4rth guarentees your freedom form unlawful searches, or seizure of property without a court order. (including privacy to do your business, in that sense). The 14th is about illegalities of creating a special class with special rules, to place things under special controls. A HOA, is a contract that is agreed to, not enforced by regulations of state or nation.
As for the lower levels of government, lesser officials often give misinformation . because of ignorance or ego, so record everything, or reduce it to paper documents.
In my troubles they refuse to answer in kind and try to buffalo through without documents , to make denials possible if they fall short. So, I dont do Phone calls. I collect whatever documents I can generate, agianst the day they try to get into punishment mode.
It is possible to sue a big mouth for harrasment on civil rights grounds, (county boards too,) as they do not have the right to limit your happiness, without incuring prejudice. We dont like that, is not good enough, a proof of threat to community or illegality must be supported.
Good luck.