Newbie to incubation


In the Brooder
Aug 25, 2015
South africa
Good morning all you good folks

I bought a 400 egg incubator which is to much for what I have but I got it for such a good price it was cheaper than the smaller types you get.

I would like to know can I open up the incubator to place more eggs in every four to seven days I want to keep record so I don't mess it up. Will this be safe for the eggs?

Is day 1 of 21 the day the hen laid her egg or is it the day I put it in the incubator?

And on which day should I candle them? Is this even necessary

Thank you


Premium Feather Member
13 Years
Feb 2, 2009
Southeast Louisiana
You’ve asked some good questions but I’m afraid this may not be a short post.

The day the hen lays the egg is not when you start counting, it’s when you start incubating. A hen can lay eggs for over a two week period to build a clutch before she starts incubating and they will all still hatch about the same time.

An egg does not have a full day’s development two minutes or two hours after you put it in the incubator. It takes 24 hours for an egg to have a day’s development. This means you say “zero” when you put the egg in. 24 hours later you say “one”. An easy way to check yourself is that the day of the week you put chicken eggs in is the day of the week the egg should hatch. That means if you start the eggs on a Friday, the 21 days of development are up on a Friday.

A problem with this is that eggs don’t necessarily hatch exactly 21 days after you start them. Whether under a broody hen or in an incubator it’s not that unusual for eggs to hatch a couple of days early or late. There are several different reasons for that; heredity, humidity, how and how long they were stored before incubation started, or just differences in the eggs. A huge factor is average incubation temperature. If the average incubating temperature is warm they can be early, if cool they can be late. The 21 days is more of a target than something you will see every time.

Sometimes, either under a broody hen or in my incubator the hatch is over within 24 hours of the first one hatching. One rare occasions they can take about three days for the last one to hatch. This is with all the eggs starting at the same time. That 21 day thing really is just a target.

You do not need to candle but you can if you want to. Candling does nothing to help or hurt incubation. I never candle eggs under a broody hen and don’t often candle eggs in my incubator. Candling is fun and can be educational. When you can even see something when you candle and what you can see will depend on your candling set-up and the color and shade of your egg shells. I have a lot of trouble seeing much inside my green eggs, especially the dark green ones. With some of those the best I can hope for is to see if they are clear or developed when I go into lockdown. Some people with good candling set-ups and white or really light colored eggs can see some development as early as three days. Until you get experience candling I would never toss an egg earlier than going into lockdown based on candling unless it starts to stink.

What you are talking about by adding eggs every few days is what is called a staggered hatch. People do it all the time but it causes certain problems. A lot of people that do it successfully have a second incubator that they use as a hatcher. At lockdown they move the eggs from the incubating incubator to the hatching incubator. That solves all kinds of potential problems.

You generally need different humidities during lockdown as compared to incubation. You stop turning eggs when you go into lockdown. How do you manage this if you have some that need turning and lower humidity in incubation while you have some needing higher humidity and no turning during lockdown?

But there is more. It’s generally recommended that you don’t open the incubator during lockdown. It is possible that you can shrink-wrap a chick by dropping the humidity after the egg has external pipped. A membrane develops around the developing chick to protect it from coming into contact with the inside of the shell. This membrane can dry out and shrink, trapping the chick so it cannot hatch on its own. This really does not happen that often. There are people that regularly open the incubator during lockdown with no or few problems. If I have a real reason to open the incubator during lockdown I open it and manage the problem. But shrink-wrapping can happen so it’s generally recommended to not open the incubator during lockdown.

Something else. The incubator is at the perfect temperature and moisture level for bacteria to grow. When a chick hatches there is liquid goop and such to mess the incubator up. The chick soon starts pooping too. After two or three days the incubator can really start to stink. I’ve had that happen in a regular hatch where the hatch itself stretched into a third day without it being a staggered hatch.

Some people successfully do a staggered hatch in one incubator like you are talking about. They have obviously developed techniques that make it work for them. Hopefully some of them will see your thread and tell you how they make it work. I don’t do that so all I can do is warn you of some potential problems, not give you solutions.

Good luck and welcome to the adventure. It can be a fun ride.


In the Brooder
Aug 25, 2015
South africa
Thank so much for the awesome advice this is an awesome group to belong to. my incubator has a tray at the bottom where I will have to open in up during the lock down period they told me on day 19 and put the eggs that must not turn on that tray in the incubator so this is worrying will see how my batch of eggs turns out. Really grateful for the advice


Jul 13, 2016
Your welcome, also lock down is usually day 18 and just unplug automatic turner and put them on the tray at the bottom, humidity 65-75% :) Good luck with you hatch!!

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