There are several factors involved, but 1 rooster about 100 yards away should not be a significant problem. 1. IF your neighbors use A/C during the summer, so their windows are closed, that helps a lot. 2. Depending on your coop design, some of the sound might be able to be baffled/muffled/diffused enough so that the crowing is not overly loud for the neighbors. 3. IF it's not overly loud, many neighbors that hate it at first, get used to it over time, and within a few months, hardly even notice it.
I have a neighbor that can barely hear the crowing, so was not bothered by the noise, however, their dog would bark every time my roosters crowed. They had to teach their dog not to bark when the roosters crowed. After awhile, even the dog got used to it, so it's not been a lasting problem.