Tips To Increase Viability Of Hatching Eggs

There are a few ways you can get chicks: buy them, let a broody hen hatch them or use an incubator. Good flock management means raising healthy birds with good genetics that will produce robust chicks (or buy from reputable breeders) and if you use broody hens or an incubator to ensure those eggs are stored in the best conditions.

There are three components that impact viability of hatching eggs: the parent stock that influence the health of the embryo and the physical egg it’s carried in; how the egg is stored prior to incubation and finally, the incubation process itself.

Depending on your perspective, I’m fortunate in that I have a lot of broody hens so have no need for buying chicks or incubating eggs, but that also means I have to contend with cranky hens wanting their crack at motherhood.

My birds are penned so they don’t have the opportunity to sneak off in the woods to their secret stash of eggs. Typically they lay until they’re ready to sit and that’s when I’m alerted to the situation and intervene. I collect eggs daily so by the time a broody hen is ready she may only be sitting on one or two eggs that were laid by flock mates or even nothing at all. That’s my cue to select a few choice eggs for her to hatch. So what do I mean by that?

Parent Stock

I only incubate eggs from healthy parent stock. Both hen and rooster should be robust with no current issues or transmissible pathogens. Some folks suggest excluding eggs from new layers because young pullets aren’t fully grown and their eggs tend to be smaller and are thought to produce smaller chicks. My experience hasn’t borne this out. The main concern with teenaged parents is the time around sexual maturity is stressful which may be the catalyst for underlying health conditions to surface and become symptomatic. If you wait until birds are at least one year old you can be more confident about their health status.

There are several pathogens which can spread from a hen to her offspring via the egg so knowing her history is important.

Collecting Eggs

I hatch my own chicks, but I also sell hatching eggs. Most folks, including me, have a preference for what they hope to end up with such as blue or green egg layers, frizzles or crested birds. In those cases, I collect eggs from specific hens. If you’re lucky the ones you want are distinctive in some way so you can identify which hens laid them quite easily. If not, it sometimes requires keeping track of which hens were in a particular nest box and collecting the eggs several times a day.

Some folks mark their eggs using a pencil, which might be appropriate for those headed for an incubator, but gets rubbed off when a broody hen rotates the eggs several times a day.

I use a sharpie to write the name of the hen on each egg if possible. It’s important for me since I keep track of the fertility rates of particular birds as well as the incidence of hatching egg fails.

It’s also nice for hatching egg customers and classroom hatch programs that follow the progress of each egg to have some information about what genetics the chicks might carry.

Storing Eggs

Left to their own devices a hen will lay about a dozen eggs before she commits to sitting. That ensures that all the eggs are incubated for the same length of time and the chicks have a coordinated hatch day. That means those eggs were stored in ambient temperatures for about two weeks before incubation.

Studies have shown that the most viable eggs are less than 5 days old. The hatch rates of those between five and thirteen days decrease by 8%-22%. I only use ones that have been stored for less than five days to increase my odds.

To ensure your best chances for a successful hatch do the following:

• Of course, eggs need to be fertilized in order for them to develop. You won’t know if the eggs you want to hatch are fertilized unless you crack them open, but you can confirm that other eggs have a blastoderm indicating that they are fertilized. Make note of any that are consistently unfertilized. Some roosters have their favourite hens and don’t mate with everyone in a flock; hens can reject sperm after mating and roosters can suffer from fertility issues. 

• Select uniform eggs with no weakness or anomalies and that have an obvious wide and narrow end. Don’t use eggs that you suspect contain a double yolk: twins rarely hatch.
• Do not use excessively dirty or poopy eggs. If you have to clean them use a dry cloth or brush.
• Wash your hands before handling eggs, but don’t wash the eggs; it not only removes the bloom, but allows moisture into the porous egg shell.
• Do not refrigerate eggs. In rare instances I have used recently refrigerated eggs due to timing or availability issues, with mixed success. If space under a hen or in your incubator isn’t a problem it’s worth a try if you’ve got something special you want to see hatch.
• I’ve had Marek’s Disease in my flock and subsequently hatched healthy chicks with broody hens without doing anything to the eggs. Some folks disinfect them with Oxine in an attempt to prevent the potential spread of the virus through dander after the chicks have hatched. You would only do this if you intended to vaccinate the newly hatched chicks before they had any contact with a Marek’s positive flock, or were integrating them with uninfected birds.
• Some chicken keepers routinely disinfect all eggs before incubation. This seems excessive as hens sit on all manner of eggs without it affecting their outcomes.
• Store eggs in a clean cardboard egg carton – Styrofoam and plastic don’t breathe.
• I have always read that eggs placed with the pointed side down is ideal because it sets the chick up to develop with its head close to the air cell. I came across a recent study that found eggs stored with the air cell down (i.e. wide side down) were more likely to hatch and the chicks had higher weights than eggs stored with the pointed side down. In nature, hens keep their eggs in a sideways position and most folks don’t store their eggs in that position. Most studies seem to support storing eggs with pointed end down.
• Keep them at 13-18C/55-65F. In warmer months this isn’t always possible so choose a cool spot in your house, away from direct sunlight. I’ve stored eggs above this temperature with no issues.
• Ideally eggs should be in a room with 75-85% humidity. Again, that’s not always possible and I have done nothing special (i.e. mist a room) to increase ambient humidity.
• Set them in a place where they won’t get disturbed by pets or kids.  
• A hen turns her eggs several times a day to ensure that the embryo doesn’t get stuck to the shell membrane, gases circulate and the temperature is evenly distributed. You don’t have to turn each egg individually. Put one or two books under one end of the egg carton and then, once daily, rotate the book to the alternate end. This gentle movement is enough to mimic what a hen would do.

Preparation For Broody Or Incubator

When giving eggs to a broody hen plan things in advance. I set my hens up in their own coop or put them in a roomy dog crate. Ensure that the eggs are placed in a well-padded nest where they won’t roll away or easily get broken. I add the hen to the nest once it’s dark so she’s not tempted to return to the place where she’s been sitting. Chickens are territorial and will focus on getting back to where she associates with her nest.

I work with my broody hens and have my practice honed to a fine art. For tips on ensuring a great hatch with a broody hen click here.

If you’re using an incubator make sure to run it for 24-48 hours before setting the eggs so you can ensure both the temperature and humidity are consistent. If you don’t have an automatic turner you’ll have to turn the eggs manually for the first 18 days.

Some folks ship eggs – I don’t as their viability rate decreases with the changes in temperature, humidity and rough handling of postal or courier services, not to mention the additional time it takes to transport them.

When you see how delicate those little orbs are it’s amazing that anything survives until hatch day. By following the suggestions above you will increase your chances of a successful hatch.