My females mice are knockout and does not produce any copulatory plug whenever kept for mating. I could not understand how should I confirm whether mating occurred or not?
if you cannot see any plugs , you can weigh your mice everyday. In general, pregnant mice gain ca. 1-2 g weight until E11 (and even more during longer development stages). Preferably, you always should weigh them at the same time. Another method is to use ultrasonic.