Thread:Balm0th/@comment-2151955-20160727205604

Are you sure about the line you added to the Eggs page?

"Be aware that is also possible to obtain a Pokémon from a lower egg tier. Example getting a Pidgey from a 5km egg."

I've never heard of this, and a quick search doesn't show any other PoGo site confirming it. I've also never seen it happen myself, and I've hatched a ton of eggs. 