Follicles grow before ovulation so you'll feel those while the female is building towards ovulation. I like to take my females out of their tubs and then open the tub a crack and allow the female to crawl back into her tub while I have a finger sticking up into the middle of the underside of her belly, once they start to grow you can usually feel a string of bumps. Imagine pulling a string of pearls between your fingers, you can feel a bump, bump, bump bump... It's not ovulation, but it's an indication that your female is headed in the right direction.