Single post in The Beginner's Guide - Help & Questions

The Shelter refreshes its contents at :04, :19, :34, and :49 minutes after the hour. When you're refreshing the Shelter, the Shelter is divided into several groups, and you're served eggs/Pokemon from one of those groups. When you refresh, you can get a different group from the Shelter. If you're adopting the same thing enough times, your chance of finding the species of eggs you're adopting increases. So, basically, if you haven't found your eggs but you just released them, try waiting until the refresh time and try again.