Hermit crab lost her big claw

Question
My daughter just got a hermit crab for her bday and I am new to this.  Right now "rainbow" is in a cage.  She has playsand on the bottom, natural sea shells that hold her food (called land hermit crab food) sponge for water and a natural sea shell to climb on.  Its always very humid in my house temp ranging from 72-81.  I also have two shells that i provided for her to grow into.  She has just lost her big claw.  Some of the web sites say to leave it in there with her, and some say to throw it out.  Will she grow the claw back and what can i do to help her?  IF she does grow it back how long will it take.  Also, when it is time for her to grow into a new shell, do i need to help her in any way?  thank you for your help!

Answer
If the entire claw fell off with the "meat" and all, i.e. there is nothing there anymore, throw it out. Rainbow will not eat the claw fast enough for it to not start stinking. If it is just the crusty shell part, leave it in there as long as you like, eating it will help her grow more shell later on. Rainbow should be fine without the big claw, but she will be a little more stressed out than usual, hermit crabs use the big claw as a shield, a hand, and a weapon, the smaller shell is normally used for drinking water. She will be able to eat powdery or wet food with the small claw, but won't be able to defend herself, so she will be kind of skittish and scared. The claw will only grow back the next time she molts, which if she is small, will most likely be within a few months. As for shells, you don't need to assist her in any way except to make sure that the shells are clean, and comfortable. It would be helpful if you put your finger into the hole as far back as you can, if anything scratches or pokes or pinches your hand, dispose of the shell, it will harm rainbow's soft body. You will also need to dump sand out of the shell and rinse it out daily, a dirty, painful shell is the worst thing you can have for a hermit crab. She will be able to change shells and stuff on her own, so you don't need to assist in that respect, hermit crabs like to do it in secret, because their soft bodies will be exposed, so you may find that overnight rainbow has changed shells without you even knowing it!