To determine the meaning of 'chickens' in this sentence, we need to look at the surrounding context. In this case, the fact that hawks are killing the chickens suggests that 'chickens' refers to both baby chickens (chicks) and grown-up chickens. Since hawks are natural predators, they would typically target both young and adult chickens for food. Therefore, 'chickens' in this context refers to both baby chickens and grown-up chickens.