Is there a 'petting zoo' type place nearby? When the Horniman had its chickens, I used to hear its cockerel crowing in the morning. Thankfully not loudly enough to awaken me but if I was already awake, I could hear it.

I know a couple of people with chickens but neither has a cockerel since they're not generally needed unless you want to breed. If you're only keeping them for eggs, you don't need one. Some councils can prohibit people keeping roosters but for the most part, it's allowed unless there are complaints of excessive noise.

When I was a student, I had a housemate with a alarm clock that sounded like a cock crowing... which we didn't realise until one day at the breakfast table, someone started wondering which neighbour had chickens.