My Holland Lop rabbit had kits and the runt isnt being fed as much as the other five,What should I do?

My Holland lop kindled 7 babies and lost one on the thirteenth of June 2010.Aside from the dead one there is a small one that im pretty sure isn't a peanut.He is half the size of the other 5 and not getting fed as much as the rest. Hand rearing him would be fatal for him,so what else can I try?