Hello -- My chickens are about 4 1/2 years old. I have collected theirs eggs and hatched chicks three times over the last year. However, my last two sets seem to be giving me problems. The last set made it all the way to 21 days and 2 pipped, but never made it out of the eggs. This last set made it to 21 days yesterday and only 2 hatched. The other 4 have not even started to pip yet and do not seem to be rocking either. The two that hatched seem to be struggling. The seem very week and are not really trying to walk or anything. The incubator temp was steady at 99.5 and my humidity was between 40-50% until day 18 when I raised to between 60-66%. Also, the eggs we get from our hens that I have not used for hatching but that we use for cooking/baking are often soft or have very dark yolks, one was even black. Is it possible that my eggs/chicks are struggling because the chickens themselves are older? Does the hens age affect the chicks healthiness? I hate seeing the little guys struggle!