With respect to hawks, I can tell if it is close versus far and approaching versus not just by sounds the chickens make. Mine may even have a different call for red-tail hawk verus red-shouldered hawk. The former can be a threat while latter in not.
So do mine, they all seem to have this strange alert sound...Or they yell really loud...at night though they make this cawing sound, like it's time to go to bed... ha haha
My 3 roaming roosters go to bed same time evrynight in tree.if anyone walks up at night they let us know. My females and other roosters trajnined to go in their hoise at night as wXell
My roosters used to have two different sounds they made for my two different dogs approaching. One dog ignored the birds and was very business-like and the roosters just gave the girls a "heads-up". The other dog had chased birds when a puppy and still got excited by the birds, and the roosters would give a more urgent call to gather the hens up a little when he approached. I love good roosters. I've got one now who is just delighted at having four new chicks in his coop, cause he has more to give treats/food to!
Mine distinguish between dogs as well. From what I have seen hens also give such complex calls but they are not intended for being heard over long distances like those produced by roosters. What is really cool in how chicks respond to hen's warning about red-shouldered hawk versus red-tailed hawk. When red-shouldered chicks simply stop what they are doing and look up at hawk. When red-tailed hawk the chicks put on after-burners and sprint to heavy vegetation and hen stays back in open and raises a major ruckus apparently to distract hawk.