To be more exact, that’s a hen. Which is the female. This is likely not his first encounter with her. My grandpa had chickens and hens, and if you visit them frequently like this they develop affection to you. I would know, because I sat in the chicken coop alot. The hens get a small maternal kick, and come to cuddle you because she wants to keep you warm, like she would do with her chicks. This means the boy has spent alot of time with her, and that just makes it more heart warming.
(Source: hannahbowl, via sextnoise)