How do you splint a duckling's leg?

I was moving my duckling's to a hen house (i was holding them in my hands) and then all of a sudden i heard a crack in one of the duckling's legs. This happened to my other duckling and it died. I don't want this to happen to this duckling!!! This is the first time we've ever had duckling's so we don't have alot of experience. I don't know how to splint a duckling's leg or do anything of those things. Please Help me out!! He/She's only 9 weeks old so i don't know if that will make a difference!!