Did you orginally have to apply for a license/permit to keep livestock? I would think that you must already have an original application/permit on file with your town and this is just an update.
I had to apply at the dept of health and then take the application to the clerk's office and then over to the police station to see the animal control officer, he set up an appointment to come out and inspect my property, in the meantime I had to get all the neighbors who abut my property to sign a paper saying they agree to let me have chickens, then after the officer inspected my property and signed my application I had to take it to the building department to have it signed (even though I didn't have any coop or even plans for a coop) and then back to the board of health with all my signatures and the neighbor agreement and paid $5.00 and had a permit.
Now they send me a bill before the first of the year each year.
Its always good when they miss a few huh, I let mine out to free range so its a little more confusing for them to count because they are running all around, he just asks me anyway.
Does your permit tell you how many you are allowed to have?