Think chicken: Think intelligent, caring and complex
Chickens are not as clueless or 'bird-brained' as people believe them to be. They have distinct personalities and can outmaneuver one another. They know their place in the pecking order, and can reason by deduction, which is an ability that humans develop by the age of seven. Chicken intelligence is therefore unnecessarily underestimated and overshadowed by other avian groups. Ref. Source 7u.
Most animals have at least a degree of cunning or intelligence and can learn from what is placed before them. Really, I don't see it as surprising a chicken can do what is described above though I do wonder what the research is meant to prove.
I never saw chickens as stupid, even if that is commonly the stereotype. Admittedly, I have also seen roosters be pretty aggressive, having completely mangled the top of the head of a hen with the one I was working for saying such behavior was normal.