I don't doubt you, but I don't think that we know the half of it. IMHO, the key to understanding chickens is to forget everything that you know about humans, because little of it applies to chickens.
I'll have a look for another paper later that has some interesting results on brian activity using a new thermal imaging process. My neice who was involved in the project sent it to me. I'm way behind on the science now...
I think one of my troubles is, I bought the chickens off a Chinese man, so when I talk to them they don't understand me. I had a bit of trouble tonight, the 3 originals were on the roost, all spread apart, so the 2 new girls wouldn't roost because it meant going in between them. I had to go in and pick the originals up and replace them closer together, then I got the 2 new girls and placed them together further away hoping to avoid any conflict.
Those lil buggers think they have the roost all to themselves by spreading out... Hopefully you showed them it won't work.. at least for tonight!
I once had the same problem. Only I purchased my chickens from a man living in Kent and they couldn't understand American English. LOL