My heart is heavy today.... we lost the little gray bunny... it passed last night.  I believe it had developed aspiration pneumonia, which is a common occurrence when trying to raise tiny bunnies.  The good news is that its litter mate is doing very well.  He/She is eating like a champ and so far no problems with aspiration of formula.  This is day 7 and to be truthful, I am surprised that I have gotten this far.  I am still cautiously optimistic with the remaining bunny.  If all goes well, within the next 3 or 4 days the eyes should be open...  and at 2 weeks I can start offering solids... but for now I have to take it one day at a time... that's just the way it is with bunnies....