Eggs have lots of nutrients your body needs. At Food Revolution Network, Ocean Robbins writes:

Whether raised in a pasture or cages, chicken eggs are potential chicken embryos (depending on if they’re fertilized and allowed to develop). But they’re more than that because eggs also contain all the nutrients that the little possible bird-to-be (the yolk) would need to grow into a tiny chick.

Along with 187 mg of dietary cholesterol (a hotly debated substance that may not be as bad for you as was previously believed) and 1.6 grams of saturated fat, a typical hard-boiled egg contains a decent amount of folate, riboflavin, selenium, choline, vitamin B12, and fat-soluble vitamins A, D, E, and K, as well as lecithin. A hard-boiled egg also provides around 6 grams of protein.

Read more here.