Hi there, I really need some advice and I've looked everywhere I can on the internet to find some advice and help but there has been no avail. I am new to incubating chicks and needs some help. I am incubating three eggs at the moment as I have recieved some over a three day period from a stables I go to. The first egg has been in the incubator for four days now and this egg is my main worry. I have candled the egg to see if there is a difference since day one, the yolk seems to have gotten darker but I am not fully sure. However, an air sac cannot be seen. Is this normal or should I be worried?