I wonder why "fowl" is okay, but "roosters" are right out? We raised chickens for many years, and while it is true that certain types of breeds have large mean roosters with some evil looking giant spurs, but they are really no more dangerous than any other pet could be, such as a poorly trained dog. And if they are kept inside so as to not reduce your property values, there is no fowl... er, foul, either.

If they are not loud or smelly or unsightly enough to bother you as a neighbor, I wouldn't worry about the chickens. Your neighbors obviously have a lot of issues that are detrimental to the neighborhood as a whole, but focusing on something that is technically wrong when it really isn't a bothersome issue has never felt quite right to me.

Are they keeping up the maintenance and cleanliness of the outside of the house and property? As far as the vitamins though... wow. These are things that you can take to the town authorities.