I'm sure it's safe to say that we can search for lionesses in the Trading Center by a specific level of fertility. However, that can be a little annoying if you want to quickly search for multiple fertilities but not all of them.
I propose the idea of changing the fertility search to something similar to how the age search works. With one box containing the regular fertility options and a second box beside of it with three options saying Exactly, Or Less, and Or More.

Comment below if you don't support or if you have ideas to improve this idea!! :)