Breedability of rabbit.

Does anyone know if when a doe is pregnant does her vulva stay bright red like when she is ready to breed.

Awhile ago we tried to use a rabbit tractor in tall grass without a bottom to grow out our young meat rabbits. They got out. So recently I was able to catch one. Her vulva was bright red but when we put her in with the buck she keep trying to run away, and stand up against the cage, and thump her back feet.