I've been very interested in chicken language for many years. I've identified over 30 different calls. It's fraught with problems. Each chickens has a different voice. It's very difficult for a human to differentiate many of the calls. Part of this is because we can't replicate them. Chickens have voice boxes essentially while we have vocal chords. Chickens will make vocal responses to vibrations which they pick up through sensors in their legs. We don't feel or hear these.
What I found made identifying calls easier was not by listening to the call or watching the the chicken that made the call, but watching what the rest of the flock do when a particular call is made. If one sees the same response from a tribe for a particular call one can often work out with a high degree of certainty what the call means to the chickens.
For example, many people think that awful racket chickens make when a predator strikes is the a warning call. But, if you watch and listen to a rooster who spots a predator, the call he makes to his hens is comparativley quiet; this might be what you are hearing. The roosters warning call is meant to be heard by his tribe, not the entire world. He gives a quiet warning, the tribe look up, if the threat is imminent they run....and then they make all that racket. So, there is a warning call and then there is a general alarm call.
There are many other calls one can identify by watching what happens which I won't go into here.
You might find this article helpful when it comes to understanding your rooster.
https://www.backyardchickens.com/articles/understanding-your-rooster.75056/
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