
It is at this stage (and probably over last few days) that she is most likely to want to be mated ans will drive the boys wild. I would keep her on lead for a minimum of 21 days, and then be wary about other dogs for another week (keep supervised and move on so that any males don't get too interested).
I looked after a freidns bitch in season and they picked her up on day 21 to take her home. they crated her for the next two days, but as their male was taking no notice left her bedhind the baby gate in kitchen while going to the loo before a walk. Shecame out to find the nephew had jumped the baby gate and mated his Aunt on day 23.
So after having sent her away to me, she still ended up having to have a morning after jab for her bitch and watch her like a hawk for the next few weeks.
aqll bitches undergo the saem hormone changes whether mated or not, so to some extent all have a phantom, but most do not have bad ones. do not allow her to mope, or guard toys or her bed. If she starts this take her pseudo pups away and any comfy bedding, even her bed, and keep up lots of excersise to keep her mind of broody things.