if a freak thing like that happens again go to tsc and get colostrum milk powder that's made for all kinds of animals. do not use kitten or puppy milk. rabbits need way more nutriants etc and they can't get enough from it once they hit a certain age/size they just get failure to thrive and die even if they make it to 5 weeks of age ya still loose them. been there done that and i know how devistating it is. sorry for ur loss. if the kits didn't nurse to get the colostrum then they have no antibodies to fight off the germs on our hands and such that kills them faster than anything.
i also use rabbit nutri- drops. it is good for stress, moving, show, nursing moms, babies when weening etc. it 100% works to help them absorb everything they r eating/drinking by bypasses the stomach and allows for absorpsion through other ways faster. always a good suppliment to have on hand in any rabbitry it has helped me greatly with shows and babies weening and had healthier litters of kits using it. its not cheap but worth every penny and it is a concentrate so lasts forever. i buy it on ebay in 8oz bottles it is the cheapest way to get it so it's about $19 a bottle.
hope this info helps ya.
mary