usually because there not ready. I found there not right after you help them out. I cant speak with ducks though.I posted my own thread, but maybe I'll get some better and quicker answers here. I have two call ducklings trying to hatch. They both internally pipped 48+ hours ago. When I saw that they were internally pipped, I made an external pip for them since they usually can't do it on their own because of their short bills. Last night I went ahead and removed a little bit of shell around the egg to help them when they're ready to zip. I checked this morning and their veins are huge. I've assisted with several hatches, but I've never had to pip for one. Did I do something wrong that's causing them not to absorb the veins, or are they just taking their sweet time? I'm terrified that they're gonna die in the shell.