My chickens get loud when something comes near them....cat,dog,birds. I think they would chase a mouse like they once did frogs(to eat). When my roo crows during the day it is either responding to birds he hears,or he is missing a lady and letting her know where to go. Yesterday he was crowing mid-day for no reason. I used to yell at him,chase him,or lock him up(for fear of the neighbors),but yesterday I just relaxed and video taped him. I was lucky to get the hawk warning and a crowing on tape!
Can the neighbors complain to the city and get them removed,or are you just wanting to be super nice and keep your animals quiet all the time? It is hard to control the animal noises.Sometimes giving food would shut the hens up,but other times they just start bawking the minute they are done eating the treats. I flip a few piles of dirt or toss out straw for them to scratch through
.If all else fails sell hens and get a different breed.Me, I would just expect neighbors to put up with the noise like I do with theirs.....except for my dogs I do get them to shut up,lol.