Just for fun. I trained a horse with a clicker & it was easy and useful to humans. Chickens? Just for me for fun, starting with distinguishing colors, maybe certain playing cards. People train dogs for agility contests and basic obedience lessons, turtles, hamsters, bunny rabbits, human athletes, all sorts of critters for useful and for non-useful purposes. A click means yes; yes, right answer. Zoos use it a ton to have animal come to fence for shots, ear exams, etc.
I first became aware of clicker training as a direct line of communication, way better than voice, when I read books about early work to train whales and dolphins. It led to what you now see at Sea World - jumping, spins, tossing balls, opening mouth to have teeth checked.
In the just-for-fun category, there are interesting short videos on uTube of a pet rabbit weaving through carrot "cones", hopping from one end of the line to another, haha. With a light wand and pellet dispenser, people train goldfish to swim through hoops, push soccer ball on underwater soccer field, or almost any swimming trick. One got her turtle to turn around three times in a row on a rock. It's the principle which seems universal, regardless of species. Who knew? Some use a click to tell a gymnastic pupil when their legs or ankles are way better positioned than they were before so they can feel it in their own body. Better than video. Better than yelling corrections/directions.
My chickens will be literally cooped up all winter due to the way below zero temperatures here in interior Alaska. I like to visit them a few times a day and it will give us all something to do besides petting. Does a chicken get pleasure from picking the right answer? Probably not. Is it entertaining? It is to me. That's all I can claim.
Interestingly enough, in watching a chicken do a complex course of ladder, hoop, going around an obstacle, down a ramp, the clicker has faded to zero. The reward comes at the end of all the steps required, so a clicker is only a training tool. Communication is what happens. I don't speak chicken, LOL.
When I trained my horse to side pass over long ground poles, the click helped him learn what was requested. After that, a mere finger or heel touch had him willingly going twelve feet or so because he understood without any clicks while he was busy going sideways; only a quiet click with my tongue and a few sunflower seeds at completion or even a stroking of his neck and verbal good boy were all that kept him complying willingly. Willing and eager to get the right answer - absolutely the opposite of making him do something for fear of correction. No correction was ever used, just no reward. Try again? Yes, right answer Mr. Horse and here is a slice of apple to complete the circuit. See why I enjoy this so much?