Well, the "eggs" aren't actually Pokéballs. The eggs are eggs that contain Pokémon and eventually hatch[0]. While Pokéballs are used to catch wild Pokémon[1].

Well, the "eggs" aren't actually Pokéballs. The eggs are eggs that contain Pokémon and eventually hatch[0]. While Pokéballs are used to catch wild Pokémon[1]. [0] http://www.ign.com/wikis/pokemon-go/Eggs_and_Hatching http://www.ign.com/wikis/pokemon-go/Eggs_and_Hatching [1] http://www.ign.com/wikis/pokemon-go/How_to_Catch_Pokemon http://www.ign.com/wikis/pokemon-go/How_to_Catch_Pokemon