Forever4You

If there is no egg, there would not be any chicken. Perhaps the egg comes from another species or something, and it hatched into a chicken. When there were no chickens, two birds that were almost-but-not-quite chickens mated and laid an egg that hatched into the first chicken. This is an evidence that eggs come before chickens.
Also, some may say that without the chicken's warmth, the egg will not be able to hatch. However, another bird, can also sit on the egg to provide the warmth, just as the mother duck sat on the swan egg in The Ugly Duckling. There may not be a consensus, but I think all evidence points to egg before chicken.

Link: https://www.sciencefocus.com/nature/which-came-first-the-chicken-or-the-egg/#:~:text=Eggs%20are%20much%20older%20than%20chickens.&text=But%20it%20doesn't%20matter,then%20the%20egg%20came%20first.