Merritt Chicks Incubating

The Merritt Library Chicks are doing their thing, happily incubating until their expected due date of May 12. We’ve had lots of questions about our little incubator, the process overall, and specific chick terminology. 

The Incubator

The incubator we use, on loan from Merritt Library staffer Ros, is a Brinsea Mini Advanced Automatic. It is a very easy to use machine and it does most of the work for you. All we have to do is add water and the incubator warms and rotates the eggs for us. A little screen on top shows us a countdown and monitors the interior temperature. If something goes wrong, the incubator sounds an alarm so we know to check in. To make sure it’s safe for educational purposes, like here at the library, the exterior of the incubator doesn’t get too hot.

The chicks need water? 

They sure do! Let’s talk about how and why. The Brinsea Mini has a water reservoir that’s divided in half. We keep one side of reservoir full for the incubation process, then fill both sides of the water reservoir on the last 24h. This process ensures that the chicks have between 11%-13% moisture loss through their shell (the shell is porous, meaning water can move through it). This helps in the production of a strong healthy chick for a couple reasons. 

  • This moisture loss makes the air pocket inside bigger so when they make the initial interior “pip” (see below), they can survive longer before pipping through the shell. Too much water can prevent the air pocket from forming properly, so the incubator is a big help. 
  • Another reason the moisture is important is to make sure the chicks don’t dry out and stick to the shell when they’re trying to get out. We wouldn’t dare cramp their style when they’re breaking out on the scene!

Learn more about this process and why it is important. 

Chick terminology

Did we say the chicks “pip”? We sure did! Here are some basic terms related to chick hatching.


The act of looking inside the egg with a bright light source to check on development. We hope to see a little shadow inside to indicate development and hopefully even movement. Now we use flashlights, but back in the day an actual candle was used. Candling does not damage the embryos inside the eggs as long as you don’t heat the egg up too much or keep the eggs out of the incubator for too long. We candled one egg on May 1 and were so excited to see an active little shadow in there!


There are two separate pips, an internal and an external. The internal pip is invisible to us, but it is when the chick breaks a hole in the membrane to get to the air pocket inside the egg so it can breath (they are so smart already!). The external pip is when we see it on the outside of the egg, and it starts as a small cracked mound. This is the that first time we see a tiny hole break through the shell and it’s so exciting!


From that second external pip, the chicks “zip” by turning around inside the egg while breaking through the membrane and shell repeatedly in order to be able to remove the top of the egg and hatch out of it. It’s a little like a really slow motion zipper on your coat, but using all your strength to break free. Once it is mostly zipped open, they give a few strong kicks and push themselves out of the egg shell. Finally free, they’re very awkward and look like tiny wet dinosaurs, but they’ll be fluffy and cute in no time!

Stay tuned to the blog for more updates on the Merritt Library’s chicks!

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