Yes, it is possible for a rabbit doe to start building a nest approximately a week after she has been bred. Nest building is a natural behavior in pregnant rabbits as they prepare for the arrival of their kits (baby rabbits).

The exact timing of nest building can vary among individual does, and it may not necessarily occur exactly one week after breeding. However, around 7 to 10 days after mating, a pregnant doe will typically exhibit nest-building behaviors, which involve gathering materials like straw, hay, or fur to create a cozy nest for her impending litter.

If you have bred a rabbit doe and notice her displaying nesting behaviors within a week or slightly after, it could be an indication that she is pregnant. It's important to provide the doe with suitable nesting materials and a private area where she can construct her nest comfortably.

Keep in mind that not all does will exhibit nest-building behaviors at the same time or with the same intensity. Some does may start earlier or later, while others may show minimal nesting activity. Each rabbit is an individual, and their nesting behaviors can vary.