I was curious about chickens so I built an incubator and ordered some eggs off of ebay. I candled them today (Day 2) and I noticed 3 had a large floating bubble in them. What is this? Are the eggs bad? Is there any chance or anything I can do?
if you turn the egg and the bubble follows you to the top of the egg no matter what direction you turn it. (like water in a balloon) then yes the eggs are bad. It is good to get rid of the eggs with the bubble and focus on the good ones. Its a mystery but I am not sure why that happens to eggs. I believe it is the due to the rough handeling of the postal system. Or it could be because the hens whom laid the eggs were really young.
Go ahead and leave them in there sometimes they'll firm up and make it...and sometimes they don't. Try to wait to candle again until day 10. By then, those that will make it have definite development and won't be injured by moving them around too much.