We were lucky last time, we bought 33 chicks and had only 1 die [ they got to stay warm and dry ] although we were unhappy about their bloodline.. Paid for pure bread and you can see some are not so we won't buy from that hatchery again.. They were insistent on getting themselves wet and I had to dry them with a hair dryer several times and that was a pain in the @.. The time before that we lost 3 of 50 meat birds but they were 15 week pullet size.. Grew them too fast by letting them eat all they wanted of high protein diet so my fault.. In the last couple of years we lost a young Buff Orphington rooster due to fighting with the adult, also lost 2 layers for unknown reasons so it happens.. Most people advise against keeping ducks and chicks together, same for turkeys, pheasant and quail.. Something about ducks and the diseases they expose the others to and feed requirements..
I big thing to watch for in their first few weeks is poo butt. That stuff can harden down there and clog em up.. Had several this last bath that I had to hold their hind ends in warm watter for a while till we could get it off and open the #2 shoot back up..