OK this might be a stretch but might be worth a try. Under PA's right to farm law there is a section that says the following:
§ 953. Limitation on local ordinances
(a) Every municipality shall encourage the continuity, development and viability of agricultural operations within its jurisdiction. Every municipality that defines or prohibits a public nuisance shall exclude from the definition of such nuisance any agricultural operation conducted in accordance with normal agricultural operations so long as the agricultural operation does not have a direct adverse effect on the public health and safety.
In the same law it states:
Normal agricultural operation. The activities, practices, equipment and procedures that farmers adopt, use or engage in the production and preparation for market of poultry, livestock and their products and in the production, harvesting and preparation for market or use of agricultural, agronomic, horticultural, silvicultural and aquacultural crops and commodities and is:
(1) not less than ten contiguous acres in area; or
(2) less than ten contiguous acres in area but has an anticipated yearly gross income of at least $10,000.
I imagine you don't live on 10 acres, it is a stretch I know, however you could argue that the city is violating the law because they are not following section 953 and you could say (if you work), that the combined income on your 'farm' is over $10,000.
It really depends on how much they want to pursue this. Since I copied and pasted from the actual law, I would say there is some grey areas for you to use. If you tell them you are covered under the state law they may back off.
Also, you could request an appeal hearing and maybe state that you wish to confront the complainer at your hearing as guaranteed under the U.S. constitution.
Tough situation and I wish you the best.