A little over a week ago we found a dead mallard female on our front lawn. Cause unknown. We were very sad of course and also knew she had been sitting on a nest right outside our house. I quickly collected the eggs hoping to save and hatch them. I bought a cheap incubator at a tractor supply and they are now in it. I don't know how long they were under their mom but thanks to candleing and comparing pictures on the internet I was able to guess they were around two weeks old. So now they have to be a little over 3 weeks and I can hear faint peeping and two have started what I believe is called "external piping?" (Correct me if I'm wrong! I live in the city and know absolutely nothing other than what I have read on the internet!) But I fear humidity was too low and they are having a hard time breaking the membrane. It has been almost 24 hours since those two (out of ten total) have made a small crack in the shell but they have made no progress since. I am scared to assist but if it seems necessary I can try! At least on of them is chirping and wiggling around a little in the shell when I talk to it. I have added a sponge and damp cloth as well as sprayed the eggs. Is it too late though? Please, any help is appreciated. Also, several of the eggs look slightly bruised- on has a long dark line that looks like a vein. It is #4 in the picture below. What does this mean? Has it died? Thanks again. Ps sorry if this is the wrong place for this post hope I am not breaking any rules!