My chickens always get up an hour or two before sunrise and it's like. You are daytime birds. Go back to sleep.
So I'm kinda half remembering a thing here but: to birds, the morning light comes earlier than it does for us. When the sun is still below the horizon, it's mostly the shorter-wave, blue end of the spectrum that comes through and light up the sky.
And birds are normal tetrapods and thus have tetrachromatic vision. They've got a whole purple/UV sensing cone in their eyes*. So like, to birds, it's already getting light while it's still night time for humans.
*wait hang on ooohhh that's why people have purple cones in TTOU, it's not arbitrary it's because that's the original tetrapod condition.
I suspect that the town's streetlights don't help either
There's a rooster a couple of houses down that always crows at like 2am
My experience with roosters was always that they crow whenever the whim strikes them, which can be absolutely any time of the day or night.
Fun fact I learned while writing a paper in seminary: in the Bible, there are four different version of a story about Peter denying that he knows who Jesus is. Jesus predicts that Peter will do this, saying that it will happen either "before the cock crows" (three versions) or "before the cock crows twice" (one version.) People who are Biblical literalists (i.e. insist that every word of the Bible must be literally true) have difficulty reconciling this, which has on more than one occasion led to Biblical scholars sitting up all night in Jerusalem to see how many times they can hear roosters crowing.
