Humidity? Side incubation? Turning 97.349 times an hour? Playing classical music? What really matters when it comes to successfully hatching eggs (for the backyard hobbyist not industrial scale poultry!) and what can you actually do to improve things? I’ve intentionally hatched (or exposed fertile eggs) from coturnix quail to various factors and also had various factors happen to my routine hatching (shipping, faulty incubators, extreme cold…). This data is NOT statistically significant, I have not exposed thousands of eggs to the same variable with controls, but it does involve hundreds of eggs and I am trained in statistics, scientific research, and have a couple peer reviewed journal articles published in a major professional journal on my CV, so this isn’t just internet rumor either. So what are the major things you can do to improve hatchability whether this is your first hatch or your thousandth?
First and foremost have a reliable incubator, which means it can maintain a steady temp for all of incubation. Temperature is the vital ingredient in incubation, you aren’t hatching anything if this is wonky. And the most vital step in this vital factor is making sure your temp is real, not just a vague number reported by the incubator, incubators are notorious liars in this area. Get yourself two or three external thermometers, make sure they are reliable and go by them, adjust the incubator temp to keep the temp at 99.5F plus or minus a degree on those thermometers, no matter what the incubator says! I had one running 105F but it assured me it was 99.5F, but it never hatched a single egg while another assured me it was the same but was running a degree low and added 3 days to a 17 day incubation! Temp is not a variable you can mess with, you can’t hatch eggs if you can’t keep it steady, so get yourself a reliable incubator and some thermometers and run it enough before hatching eggs to know it’s quirks and how to adjust it, including drafts, insulation, sunlight, heat vents, etc that might change the ambient temp.
The other vital factor is egg quality and fertility, so good husbandry, good nutrition, fertile birds, avoiding lethal genes (like homozygous silver in quail), minimizing inbreeding, all contribute to hatchable eggs, obviously you only have certain control over this even in home raised eggs, but again, nothing will hatch if you don’t have good starting material.
Temp is no surprise, how about humidity as the next biggie? Actually no, I was floored to discover humidity isn’t one of the biggest factors influencing hatch rates. My cheap little bubble incubator is horrible at humidity control (20 or 80%, pick one!) but it still pulls off 90% hatch rates even when I intentionally hatch at the extremes! So while you should keep your eggs within the recommended ranges for your species, you won’t destroy your hatch rates with a sudden drop or spike, aim for an average rather than worrying about highs and lows.
Turning? Yes, turning is huge, especially the first half of incubation. I intentionally ran a couple No turn hatches and had a faulty turner that tanked an otherwise normal hatch, expect 50% hatch rates if your turning is wonky. Even hand turning three times a day is enough to prevent issues if you aren’t positive your turner is reliable.
Egg position? Angled, side, upright, which is best? Especially for saddled or damaged air cells from traumatic shipping? I’ve hatched two groups of shipped eggs with saddled air cells, one I set upright wide end up and the other just did normal side incubation, absolutely no correlation between position, air cell integrity and hatch rates! The problem was shipping trauma, not air cell anatomy, chicks hatched just fine from wonky eggs and died in shell in normal eggs (and vice versa), in general incubation position seems to be a rather minor detail.
Dirt, washing, wet eggs, washing off the bloom, sanitizing eggs? I’ve tried very hard to induce a bacterial overgrowth in eggs by scrubbing, soaking, etc but can’t do it. Cracks in the shell or the rare contaminated egg (say secondary to salpingitis in the hen) are the only reliable way I’ve found to destroy egg integrity. Removing gross contamination and excess fecal material is a good idea for incubator sanitation and chick exposure but as far as hatching success, a little dirt or gentle cleansing isn’t going to hurt anything so you do you.
Candling, handling, opening the incubator, moving eggs around within the incubator, cooling at room temp for a couple minutes? I candle daily, perhaps obsessively, that’s just me, I love the development stuff, besides for the rare egg I drop and crack it doesn’t seem to hurt hatch rates. I like to rotate my eggs within the incubator as it evens out hatch times but doesn’t increase hatch rates, just shortens hatching interval. Messing with your eggs isn’t going to wreck a hatch, have you watched a hen?!
The final most important hatch rate factor is actually a combo but can be summed up by the word stress. Your entire bird comes from the genetic material contained in a single cell before incubation begins, a typo or damage to that original data can spell disaster, while a more fully developed embryo with millions of cells can handle typos galore. Anything that damages the genetic material during pre or early incubation can tank hatch rates. These eggs actually develop very well but tend to die as incubation progresses, some even hatch but are more prone to deformities. Time is in this category, once your eggs hit a week to ten days old preincubation your hatch rates start to decrease. Cold exposure, so fridge eggs or winter eggs exposed to near or freezing temps for even a couple hours cuts hatch rates in half. The same goes for heat spikes above 103 in or out of the incubator. I don’t have data but storing eggs for days in the mid seventies or above probably isn’t a good idea. Physical trauma is definitely an issue, so no juggling hatching eggs, but moving or turning them once a day preincubation isn’t a bad idea either, it won’t hurt and might help. And obviously shipping combines time, temp extremes, and physical trauma no matter how carefully they are packed or how quickly you try to ship them.
So how do you improve hatch rates? Start with quality, fertile eggs. Have a reliable incubator you can maintain a steady temp in and adjust accordingly. Make sure your eggs are turned at least 3 times daily the first half of incubation. Treat your pre and early incubation eggs like royalty-incubate within a week of collecting, keep the eggs between 40-70 degrees (if possible) until incubation, turn or jiggle them daily, and don’t toss them down the stairs. Yep, it is that simple! This is not to say you can’t ship eggs or incubate in the winter, you most certainly can, but have a realistic expectation for hatch rates. 50% In February at -25F overnight or on traumatized week in the mail eggs isn’t a bad hatch rate and may just be a miracle! There are a few things you can control with hatching, but most of it is out of our hands, and stuff happens to everybody, even experienced hatchers, don’t give up, rather learn and try again. Happy hatching!
