Yup, pretty much what's already been said. Drowning is really nothing to do with high humidity at lockdown. It's due to the chick being over-humidified throughout the first 18 days of the incubation. But because the chick doesn't actually die till lockdown (when it starts breathing air and inhales the excess fluid in the egg) people blame it on the lockdown humidity, which is almost never to blame. I always run my lockdowns at 70%+, sometimes as high as 80% and I've never had a drowned chick. One lockdown the humidity got up to 90% and sat there for a whole day, and they still all made it out fine and dried off no problem.