A bird which is unaware that a foot may crush their eggs or a wild animal can break them?

Your question assumes that a bird has a sense of time passing - whether animals do or not has long been a point of debate as it indicates a sense of self-awareness and a lot of ethical debate hangs on that. So far as I am aware, that sense remains unproven except in humans although there is a large body of evidence that it exists in apes, but not birds.