"To hatch the egg" means to work on or complete a task or project. It refers to putting in effort and dedication to achieve a desired outcome or goal. Full definition
I also discovered another irritating problem out in the countryside; the game has a horrible habit of failing to register distance travelled, and thus won't hatch eggs. (wolfsgamingblog.com)
You will need a copy of Horton Hatches The Egg, a nest of plastic eggs, and something to put inside a few of the eggs (e.g., candy, stickers, small toy). (myplaytherapypage.com)
It takes care of hatching eggs and larvae left behind so they can't reproduce which completely stops the infestation. (geekwrapped.com)