Hen pecked

My son and I went to the city farm and looked at all the animals. As we were walking and talking with the goats, I saw a stray chicken and we watched it. It had escaped it's pen and was wandering around. We went down towards the chickens and my son was eating some crisps. I hgad told him too keep a tight grip on them and not too feed the animals with them. Out of nowhere the chicken arrived and sensing an easy meal, snatched me son's crisp that was in his hand. Cue, terrified son and much frenzy amongst the other chickens! Son was ok in a few minutes and I was just about to return the chicken to it's enclosure when more visitors arrived and I just left it there.