It really depends on the body shape and % body fat of the girls ... some girls it's easy to see the swell from building (lots of people mistake this swell as an ovulation or as being gravid).

I don't go by any external visual "looks" ... I just feel for follicles ... it's the single most important thing a ball breeder can learn to do ... once they reach a certain size BAM! ... ovulation is a lock!

Sounds like you're doing everything right! ... Hang in there.

-adam