incubation day 30

Well Last night I cracked the eggs from my first two ducks and they were dead.  I cried.  No i didn't kill them but it may have been something I did while incubating them.  I didn't have my humidity up enough and it dried the inside of the egg up.  Everything in the egg was dry and hard.  So I raised the humidity, and was told that it would help.  Another lady that the ducks originally came from said that they have had to zip the eggs open and then let the ducks make their way out because all they feed them was laying mash.  So I have changed the feed to half corn and half laying mash, maybe it will help my chicks get out.  I also have 6 of my chicken eggs in the incubator and 5 are fertile.  We are going to keep incubating eggs because we are planning on have chicks to eat.  I have 2 ducks due the 23rd, lets everyone pray for my ducks.