After a few more sessions with Lucy I was certain she associated the sound of the clicker with treats. To eliminate competition from the other hens I carried out the remainder of the training with Lucy in the coop while Pete and Ethel remained in the run. The run is along side the coop so Lucy could still see and hear her colleagues, preventing her from becoming anxious due to separation as chicken are social animals. During each session I allowed her to decide when she had enough and would be returned to the run with the others.
Lucy Meets The Queen:
I could continue to work with Lucy until she could find the Queen of Hearts in a pile consisting of nothing but face cards but the ultimate test would be to condition her to peck a different card (re-conditioning). I could also attempt higher-order conditioning, pairing another neutral stimulus, such as a flashing light with the sound of the clicker but it is more likely that I will build obstacle courses for them to run.
My inspiration for this experiment came after viewing (Chicken Training: The Art and Science of Animal Behavior” by Dr. Sophia Yin, DVM, MS. Dr. Yin is an internationally acclaimed veterinarian and animal behaviorist.