There is no italicized pronoun, but since there is only one present in the sentence, I give you this answer:
When chicken eggs are hatched, they are weak and barely able to move around. They here should refer to the "chicks" However, in the sentence it looks like it refers to the "chicken eggs". This is incorrect. The pronoun, then, is an (2) implied antecedent and needs to be stated. Instead of the given sentence, one should say: When chicken eggs are hatched, the chicks are weak and barely able to move around.
