How often do yall candle??
Being as this is my first hatch...I think I wanna do it more than I need to
From my viewpoint, the only purpose of candling is to remove dead eggs that could potentially leak bacteria and/or explode. Therefore, I think no more often than every 5-7 days would be needed. LESS is better. The more you open the incubator, the more you cause fluctuations to humidity and temperature. I've been told that in the later stages, sudden and frequent drops in humidity leads to shrink-wrapping. In the early stages, temperature is more critical to proper development.
Also, handling eggs exposes them to whatever germs, oils and other contaminants you might have on your hands or the candler. It also greatly increases the chances of damage or death from mishandling. I think most of us here have accidentally dropped an egg during candling.
Again, from my viewpoint (I'm no expert!), it might explain why eggs hatched under broody hens don't have great hatch rates. Broodies will leave the nest for an extended time once a day or so to eat, drink, and poop - tromping through whatever contaminants & bacteria are on the ground, and then transferring that to her eggs while possibly cracking or crushing eggs. By incubating and keeping those variables controlled, we attempt to improve the odds.
(disclaimer: I didn't use to think this way, but 6 years of exposure to the smart and well-experienced chicken breeders on this site have enlightened me, and I've changed my opinions.)
So... sorry for the diatribe....
* Beginning of Day 0, when I first set the eggs. I'll weigh them, check for imperfections, and mark air cells, and make notes of any concerns. I note in my log the date and time of the start of incubation. After that...
* Once between Days 5-7 to remove clears and obvious quitters, and check for signs of good progress. I try to get through this as quickly as possible and don't waste time marking air cells nor weighing them. If I can see it has expanded, then it's good enough at this point.
* Once between Days 10-14, but I might not even remove them from the tray - I think this period is the most critical time to prevent any jostling of the eggs. I'm just looking for good progress (I can often see movement without taking them out!), expansion of the air cell, and to remove early quitters. ONLY if there's doubt, I'll remove it to candle more carefully, weigh it, and then decide.
* On Day 18, an extended candling - to weigh them again (should be about 12% weight loss by this time), check the air cell, remove quitters, and make notes on my log of any concerns. If the air cell is angled towards one side or another, I'll make sure they're marked clearly and placed with the air cell UP. And of course, I remove the turner, bump the humidity, and we are in lockdown until hatch.
* Any eggs that have passed Day 21 with no external pip. I can't see much, but I'm checking for an internal pip if possible and listening carefully for chirps. On or after Day 22 and still no progress, I might make a safety hole in the air cell to see what the heck is going on in there.
And that's it. I don't open the lid nor touch them at any other time, not anymore. Hope this helps.
