my 21 month old has lost 2 of her toe nails. she sat there tonight picking her big toe nail off,eww. but when she took it off the was a new one under neath. she has lost one before and it grew back ok. now my other child had this as well when he was her age. is this a normalthing?? do all children lose there toenails at some stage? or are my kids just toe nail pickers