Leaving the alley today at ORD was listening to Ch. 9. Had the chance to hear a funny conversation between an American Eagle flight and the tower. As a bit of context, the AE flight was inbound and from what I could tell, somehow got out of sequence on the way to their gate (this appeared to be a result of communications from the tower). Regardless, interesting exchange:

AE: "Sorry about all that, we're not from around these parts."

Tower: "Ha! There are only about 200 of you around here, and about 50 blue chickens."

So....what are the blue chickens?

Thanks for all your time and effort in answering all of our questions!