Ducks take a long time to hatch (up to 3 days for the entire process). About 24 hours after they made their initial pips they should start to slowly crack around the rest of the shell ("unzip"). That part can also take about 24 hours, so just be patient. They take long breaks between steps and will not finish hatching out until they are completely ready inside their eggs. They need time to finish absorbing the yolk and drawing in the remaining blood from the vessels in the inner membrane. Often times when people help it is too early and the yolk will either not be absorbed yet, or blood vessels will be broken and the ducklings can bleed out.
No helping! That most often does more harm than good. Patience is the key with hatching ducklings.
Just sit back and watch the magic happen. ^-^
