
Hi,
Rosie is likely to bleed for about 21 days, and will most likely be fertile between 11 - 15 days
BUT successful matings (resulting in pups) have been known as early as Day 2 and as late as Day 22! So for about 3 weeks don't let her outside unattended, not even in your own garden, and don't let her off the lead when there are any other dogs in the vicinity. It is sensible when you take her for walks to drive her to a different (quiet, dog-fee) place, and drive her home again so that she doesn't leave a treasure trail for all the local Romeos!
Hope this helps!
:)