How to Hatch Fertile Eggs

Everything You Need to Know About Prepping Eggs for Hatching

Before placing eggs in your incubator, it’s important to start with clean, fertile, good-quality eggs. Odd-shaped, dirty, or cracked eggs won’t hatch well—and if they smell bad, toss them right away! For best results, use eggs from healthy hens that are not too young or too old, and never store them for more than 7 days. Each day they sit, hatch rates go down, and the incubation time gets longer. Always store eggs with the pointy end down.

Never clean the eggs with water or wipes—gently brushing is safest so the eggs can still “breathe.” Clean the correct way to protect the egg bloom. The “bloom” is a thin, invisible coating on the outside of an egg that protects the baby chick growing inside. It keeps out germs and dirt by sealing the tiny pores in the eggshell. This natural barrier is super important because it helps keep the egg safe and healthy during incubation. That’s why you should never wash eggs before putting them in your incubator. If they’re dirty, gently brush off loose dirt, but leave the bloom alone—it’s doing an important job!

If you’re using shipped eggs, keep in mind that vibration and temperature changes during travel can lower hatch success. Also, avoid using a permanent marker to label your eggs—it can actually harm the embryo. Instead, label the tray or use a pencil.

Finding Eggs Suitable for Hatching

The best age for a hen to start laying eggs suitable for hatching fertile eggs is usually 6 to 12 months old. Here's a breakdown:

• Too young (under 5–6 months): Hens might start laying small or irregularly shaped eggs (fairy eggs). These early eggs often don’t hatch well because they're not fully developed or consistent.

• Ideal age (6–18 months): Eggs from hens in this age range are usually the right size, have strong shells, and better fertility rates. This is the best time to collect hatching eggs.

• Older than 2–3 years: Fertility and hatchability can start to decline as hens age, and older hens may lay fewer eggs.

For the best hatch rates, also choose eggs from healthy, active hens and roosters between 8 months and 2 years old. Avoid using eggs from pullets (young hens, the chicken teenagers) just starting to lay or hens past their prime laying years.

Misshapen, dirty, or cracked eggs rarely hatch—and if an egg smells bad, it should be thrown out immediately!

How to Use the Egg Candler

Egg candling is the process of shining a light through an egg to see what’s going on inside. It's usually done around day 7 to day 10 of incubation, when early development is easier to see. A good, strong egg candler—or even a small LED flashlight in a dark room—can help you spot blood vessels, a moving embryo, and a dark growing mass inside the egg. These are all signs that your egg is developing normally.

If the egg looks totally clear after 10 days, or has a blood ring (a circular red line with no development), it has most likely failed and should be removed to avoid contamination. If you’re unsure, wait a few more days and candle again—just be careful not to disturb the temperature and humidity in the incubator too often. Around day 18, stop candling and let the eggs stay still to prepare for hatching. At this point, a good egg will be mostly dark with a visible air cell at the large end.

What Fertile Eggs Look Like by the Day

There are different types of candlers available. Basic handheld LED candlers are budget-friendly and work well for lighter-shelled eggs. High-intensity candlers are better for dark or speckled eggs like Marans or quail. Some advanced candlers come with adjustable light strength or rubber seals for a better fit over the egg. No matter what type you use, candling helps you track progress and increase your chances of a successful hatch.

When hatching eggs at home, not all eggs will turn into baby chicks—and that’s okay! Some eggs may be fertile but stop growing partway through. These are called “quitters.” 

You might see a dark shape that doesn’t move or a clear ring of blood inside the egg called a "blood ring." This means the chick started to form but didn’t survive. When candling and see no veins, a bad smell, or the inside looks very still after many days, it’s time to remove that egg. Watching closely helps keep the rest of your eggs safe and healthy.

Is Your Hen Healthy Enough for Fertile Eggs?

To know if a hen is healthy enough to lay fertile eggs, watch for these signs: clear, alert eyes; clean nostrils; smooth feathers; and an active appetite. She should lay regular, well-formed eggs with strong shells and have a bright red comb. Her legs and feet should be strong and free of swelling or sores, and droppings should look normal. Fertility also requires access to a healthy, mature rooster. Avoid using hens with signs of illness, parasites, or irregular laying patterns, as these can reduce hatch success.

Setting Up the Perfect Spot for Your Incubator

Your incubator or hatcher should be placed indoors in a room with a steady temperature between 68°F to 82°F. If it gets hotter than 86°F, the incubator may overheat. Choose a level surface away from direct sunlight, about two feet from any wall so air can circulate. Make sure the room is well-ventilated—fresh air is key because growing chicks give off carbon dioxide. If needed, use a small fan or open a window to keep air moving. To help your incubator do its job, aim for room humidity around 50-60%.

How to Store and Hatch Eggs Successfully

Store clean, fertile eggs for no more than 7 days. Use a brush to clean eggs, not wipes or water. Set eggs in your incubator with the sharp end pointing down. Don’t mix duck or goose eggs with chicken or game bird eggs—they carry different germs. Eggs lose moisture during incubation, so humidity control is key.

Incubation Basics for Chickens

Chicken eggs hatch in 21 days. From day 1 to 18, eggs stay in the setter trays and need to be turned regularly. If your incubator doesn’t turn eggs automatically, turn them at least 3 to 5 times a day—always an odd number of times to avoid resting on the same side overnight. Stop turning on day 18. 

Mark each egg with an “X” and “O” to track turns, and always handle with clean hands. Regular turning keeps the embryo from sticking to the shell.

On day 18, move them to the hatcher trays and stop turning. Keep the incubator closed from day 18 to 21—opening it can dry out the chicks and trap them inside their shells. Humidity settings matter:

Days 1–18: 50–60%

Days 18–21: 60–65%.

Opening the incubator too early, especially between days 18 and 21, can cause the humidity to drop. This can dry out the eggs too fast and make the inner membrane stick to the chick, a problem called 'shrink-wrapping.' When this happens, the chick can get stuck and may not be able to hatch or survive.

Note: Always follow the instructions provided with your specific incubator brand for best results. Humidity levels may vary slightly depending on your model.

Why You Need a Hygrometer

A hygrometer is a tool that measures humidity, and it's a must-have for keeping your eggs in the perfect environment. Many modern incubators have one built in, but if yours doesn’t, grab a small external one to place inside. It helps make sure your chicks have just the right moisture to develop and hatch safely.

What to Expect as a First Time Hatcher

As a first-time hatcher, expect a hatch rate of 50–70%, though results can vary. It’s common for not all fertile eggs to hatch, especially if you’re using shipped eggs or a manual incubator. Some chicks may take longer to hatch, and not all will survive. You'll likely experience a mix of excitement and nerves—patience is key during the final days. Focus on learning, keeping good notes, and improving your setup for next time!