Chick anxiety?

https://www.sciencedaily.com/releases/2024/10/241024130804.htm
These researchers are trying to measure bird depression and anxiety by vocalization, but it looks like they have the wrong model.  What they did was put two chicks into different environments.  One chick was put in a box by itself, and the other chick was placed in a box with a mirror.  The chick with the mirror was fooled into thinking that it was not alone, but the chick by itself started giving a different call. There likely is anxiety in being separated from their hatch mates, but the call they recorded is likely the gathering call.  It is the call chicks make when they are lost from their brood, and gets the mother hen to find them.  There is likely no more anxiety in the call than when you flush a covey of Bobwhite quail, and a few minutes later you start hearing the gathering call that gave the quail their name.  The birds are just trying to get back together.
Chickens imprint at hatching, but it isn't the same as when ducklings or goslings imprint.  Chicks seem to imprint on their environment (brood mates as well as their mother) ducklings imprint on specific individuals.  Chicks may never imprint on any parent, but they do seem to imprint on their hatch mates.  If they are hatched in isolation they may not imprint on anything.  Ducklings will imprint on the first human face that they see out of the incubator, but chicks do not do this.  The chicks will still give out the gathering call when separated from their hatch mates.
These researchers likely need another model to measure anxiety.  What they are currently doing is differentiating the gathering call from normal inter chick vocalizations.
Ron Okimoto