Once a hen goes broody and starts sitting on eggs, it takes about 21 days for the eggs to hatch. It also takes about 21 days for eggs to hatch in an incubator.
If you’re hatching eggs from your flock, there is likely to be some variability in how long it takes. Don’t be surprised if it takes 22 or 23 days for some of the eggs to hatch. The most robust chicks will hatch within the first 23 days, as discussed in more detail below.
In this article, I’ll compare the pros and cons of hatching under a hen to hatching in an incubator, and I’ll give you some tips for both approaches.
Let’s look at two different scenarios.
Scenario 1: Your broody hen just started sitting
If your hen just started sitting, what I’m going to say next will seem counterintuitive. But stick with me.
Remove the eggs that she’s sitting on every day for the first few days that she’s broody.
One, if she isn’t very serious about sitting and hatching eggs, then she’ll quickly get annoyed with you for the disturbance, and she’ll stop sitting. That’s a good thing. If she’s an unreliable sitter, it’s better to discover that early, not after she’s been sitting for two weeks.
Two, it gives you a chance to replace the eggs under her with the eggs that you want to hatch. Those may be different eggs than what she chose.
Three, it lets you start incubating the eggs under her on the same day. That way, they’ll hatch close to the same time. If you were to just let her keep sitting the original eggs, chances are, some of those eggs are older than others. That could result in hatching that’s spread out over a week or more. You’ll get better results with the tighter hatch window that you get by starting incubation the same day for all the eggs.
For more information about all this, see my article on hatching chicken eggs under a broody hen.
Scenario 2: You are using an incubator
If you’re hatching in an incubator instead of using a broody hen, my personal experience has been that some eggs will hatch at 21 days, but other eggs will take 22 or 23 days.
I normally stop incubating eggs on day 23. In my experience, chicks that hatch after the 23-day mark tend not to be as robust. The more vigorous chicks develop more quickly and break out of the shells closer to 21 days.
Once the chicks hatch, let them dry in the incubator, then transfer them to a brooder.
Which is better? A broody hen or an incubator?
It depends on what you’re trying to do.
A broody hen (one that is in the mood to sit on eggs) can save you a lot of work. I think the chicks she raises tend to be smarter (or at least better trained) and are better able to take care of themselves. She keeps them warm. She teaches them to eat. She teaches them how to find food. A good broody hen will even teach the chicks how to hide from predators.
Chicks that are hatched in an incubator and then reared in a brooder under artificially produced heat aren’t going to have all this extra training from the hen.
That said, broody hens aren’t very predictable. But some are better than others. You don’t know exactly when they’ll go broody. They’re more likely to brood during spring, but exactly when they’ll start is unknown.
Second, not all broodies will stick with sitting all the way through to the hatch. Third, some of them will hatch your chicks fine, but they won’t take good care of them. And fourth, some broodies eventually get tired of raising chickens and become brutal toward one or more of the chicks at some point.
Broody hens differ in their mothering instinct. Some make great mothers. Others make terrible mothers.
Broody hens ought to be housed separately from the rest of your flock so they can sit and hatch undisturbed by other hens, and so they can raise their young without the risk of other chickens harming them (which they can and will do at times). The broody house also needs to be secure enough that animals like skunks cannot dig under it and eat the eggs or the chicks.
If you have a good broody hen, she can potentially save you some work and raise better-taught chicks. However, an incubator can work very well and is more predictable.
What percentage of eggs will hatch?
It depends but if everything goes well, you can expect around 70-80% of them to hatch.
After some experimentation, I’ve found that I have the highest hatch rates when incubating at 100.0 (F), which is the temperature recommended for this incubator, and a relative humidity near 45% for the first 18 days of incubation. On day 19, I increase the humidity to around 55-65% for those last few days of incubation. Be sure to consult any manuals or documentation that come with your incubator for temperature recommendations, since it will vary depending on the type of incubator.
Most chicken eggs hatch at 21-23 days under a broody hen or in an incubator.
Whether to hatch under a hen or in an incubator is a matter of personal preference, since each approach has advantages and disadvantages.
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