It is very hard to keep them alive at this age. Of the 45+ from Kooah's brood, only 2 survived. Mistakes (putting two together and not cordoning off hardware) may have been responsible for two deaths but the rest just disappeared.
so sorry for your loss. We know so little about there needs at this age. Just think about it like this there are scientists trying to do what you did and have unlimited resources and most have no better luck then you did.