Well I wouldnt say mine are EXCEPTIONALLY smart, but they are in the house so have MUCH more human contact/interaction than a normal chicken would.
My two oldest girls and my little showgirl know NOT to go in the living room. This was never rewarded with good behavior either, this was a "spankin" if you go in there, and they learned fast. The one barred rock I have tho, she wants to push the envelope and goes in there anyway.
They all four know their names, when they are sleeping and we talk about them, you can mention their name, and they will coo at you, in turn, pretty much. Its cute! lol Even little Dash, who was not the brightest bulb in the socket to begin with, has learned her name. She has I guess ACCUMULATED knowledge. And she hates being bawled out. She has learned what to do and what NOT to do, just by watching Lily. lol I was serious when I posted that pic of them, where Dash was saying "Am I in trouble for this?" for dustbathing in the entryway. She absolutely hates being in trouble, not sure why.
My other girls know the words "Get down", "Jump" "Outside" "Grapes" "No" and "HEY!" which I have mentioned before, gets more response than no. lol They must think when I finally say "HEY!" I mean business. They also know "bedtime" and will jump in their box. I have never really taught them tricks, it would be interesting to try, but am at a loss where to start.
I know one person on here that had paper trained her house chicken, I think I only have one I could do that with, but no way could I do it with the other chickens around, they tend to reinforce each others bad behavior sometimes. lol