Keep pairing..... Unless you have an ultrasound it is impossible to figure ou exactly when the female is ready!!!!! This is why we pair every 3 days to make sure!!! Keep pairing. Im having the smae problem this year and had it last year also but as soon as december rolled around locks like crazy. Time is key here!!! Hope that helps. Ive been pairing since oct 1 and seen 1 lock outta 10 pairs