From PokéHeroes Wiki
egg and one Pokémon shown on the Index page. While they are on the Index Page, they will gain twice the experience as usually if they are interacted with. They are replaced every five minutes at maximum with other random Pokémon or eggs whose owner has interacted with the previous chosen Pokémon. If an egg hatches in less than five minutes, it will be replaced with another one.
If you click the egg sprite or Pokemon sprite, its summary will open up.