Neither. Both have calories and cholesterol. Eat meat in small quantities with a goal in mind to stop eating it completely.
Or, perhaps in the grand scheme of things - neither is important or both equally important. Is a leaf any more important to the universe than a baby human?
"chicken" since its the first one mentioned, in your question Please Register or Log in to view the hidden image!
Eggs are a foundation of many receipes. We can get along without chicken. So, I say eggs are more important.
But, if you only had one chicken and one egg. And there would never be any more of either. Which would you savor most?
Have you ever tasted any other birds' eggs? Maybe they all suck and you would be making a huge mistake.
But chicken is so bland. Besides, there are plenty of other birds to eat, e.g. geese, ducks, ostrich etc.