She will be within 5-7 days. This is the period of mice. Hence you do not need to know, you just have to keep them together for at least 7 days to be sure. Many breeders keep them together for two weeks (to cover two periods) or until they see first signs of pregnancy.
Btw, from my experience with ladies I can tell you that it needs more than being in season to accept a buck... :lol:
Best regards, Roland
Chilloutarea Mousery - Tricolor , Splashed , Merle , Recessive Red
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