My chickens respond to their names and also know our morning routine. They wait patiently for me to do a couple of chores in the coop, knowing that food is on the way. They do recognize our voices and and will hide if strange people they don't know come into the yard.
Of course there is some conditioning involved here, and they definitely will come running if they hear the can of treats or see the container. They jump up and try to grab it. But all animals experience behavioral conditioning, even human beings.
Maybe it's because they are our pets and not our livestock, that we think they are smart. There are also only a few of them and they get lots of individual attention, so we know their individual personalities and indiosyncrasies; and they know us as well. When we return after a vacation they practically do back flips when they see us even though they have been fed and cared for by a neighbor.