it would be interesting for sure to find if and how anyone has supplemented calcium for developing girls. I would think though that if you are feeding good quality rats/mice then they should be getting the right amount of calcium, unless the female has a type of issue health wise that is not allowing her to uptake the calcium the way she is supposed to.I breed my own rats and feed high quality food, so i thought for sure they would be uptaking enough calcium from that. Another thing to consider is giving them to much calcium and what issues that may cause.