EDITOR'S NOTE: This is an article that I wrote when I was 15 years old and submitted to a magazine called Mother Earth News. They rewrote my article themselves and never paid me. Given that at that time they only paid about $20 for an article, I felt cheated. I never wrote another article for them and subsequently cancelled my subscription. This article has been shelved for several decades now, but I decided to bring it out of mothballs because several people have expressed interest in building their own incubators.

Build "Matilda" - an Electric Hen for Less Than $10

by Dennis Hawkins

When hatching eggs, its always best to use a broody hen. However, sometimes hens aren't very cooperative when it comes to being broody at the right time. Some breeds of chickens don't go broody at all. In order to hatch eggs from non-brooding hens, you either have to find a broody hen somewhere to do the job for you, or you have to use a man made incubator.

Such incubators are very expensive. Some cost as much as $30. Such high prices are often unjustified. This article explains how to build "Matilda" - an inexpensive electric incubator that can run on both 120V house current, or 12V DC power from your car's cigarette lighter. The best thing is that the entire setup can be made for less than $10. Depending on your shop, it may not cost anything at all.


The parts for building "Matilda" are very easy to come by. I happened to have all of the parts required in my shop so it wasn't necessary for me to purchase anything. Other people may have to buy a few items.

Materials Needed Cost
30 Quart Styrofoam ice chest $1.50
Discarded table lamp or lamp making kit $5.00
Thermostat switch *.**
Screw base 12 volt - 25 watt light bulb $2.00
Screw base 120 volt - 25 watt light bulb X.XX
Electric tape X.XX
6 foot extension cord X.XX
Cigarette Lighter plug $1.50
Hook up wire X.XX
Total Cost $10.00

All of the above items can be purchased at larger hardware stores if necessary. Items marked with "X.XX" are considered "Odds and ends" which, I hope, most do-it-yourselfer's will already have in their shop.

The thermostat switch that I used came from a worn out electric water heater that had been discarded by someone and left on the side of the road. You can also buy new thermostats in the hardware store. Just be sure that the thermostat will go down to 100F. Not all water heater thermostats will.

An old lamp or lamp making kit furnishes most of the additional wiring. If you plan to run "Matilda" on 12 volts, then you will also need a 12 volt screw base light bulb. These bulbs are much harder to find than regular 120 volt light bulbs but they look almost identical. A quick connect cigarette lighter plug can be purchased at Radio Shack and is necessary to run the incubator on 12 volts.


The only tools required to build "Matilda" are a screwdriver and a sharp pocket knife. First, use the pocket knife to bore out a small hole for the lamp extension tube. The extension tube is placed through the styrofoam and is 3" from the top. Position the bulb in such a way that it doesn't get too close to the styrofoam. It is also necessary to cut a few small air holes. The air holes should not be too large or else the heat will all get out. It is not necessary to mount the thermostat. As a matter of fact, it is best to just let it rest on the bottom of the ice chest.

Refer to the wiring diagram and the drawing and you should have no trouble at all. The lamp base must be wired after the extension tube has been placed through the hole in the styrofoam because the wires feed through it. When completed, tape all exposed, bare wires and connections so you and your chicks don't get shocked. After that, screw in a 120 volt (standard base) light bulb and plug "Matilda" in. If there are any sparks, fire, smoke, or buzzing, then you should take this as a hint that you have done something wrong. When properly built, "Matilda" will blink on and off to automatically regulate the temperature inside.

"Matilda" is primarily designed to run on household current; however, it can easily be converted to run on 12 volts. This feature is handy if you live in an area where there is no A.C.. To do this, you simply remove the 120 volt light bulb, replace it with a 12 volt light bulb with the same base, and attach a 12 volt adapter. The 12 volt adapter is made by cutting off the male plug end from an extension cord and replacing it with a cigarette lighter plug. The incubator is then ready to plug into your car's cigarette lighter. Just be sure to remember to change light bulbs again before you plug the incubator back into A.C.. Otherwise, the 12 volt light bulb will burn out in one bright flash.


The incubation period for chicken eggs is about 21 days. Each day the eggs should be turned over at least once. An easy way to remember is to write "EVEN" on one side of the egg and "ODD" on the other using a pencil. On odd numbered days, the "ODD" side goes up, etc. In order to keep eggs at a constant temperature, "Matilda" uses a small thermostat which should be set at about 100F - just enough so that the eggs feel slightly warm to the touch. At that temperature, the egg shells have a tendency to dry out so you should place a small dish of water inside the incubator to keep the air - and eggs - moist. Also, it is a good idea to put a few paper towels in the bottom of the incubator just before the eggs hatch in order to catch all the droppings. After they hatch, the chicks should be removed and put in a brooder. If they stay too long in the incubator, they will peck the styrofoam until there is nothing left.


Although "Matilda" may not look as good as expensive, store bought incubators, it is just as (or more) reliable. The ability to hatch eggs on 12 volts is a feature that most store bought incubators lack. Therefore, hatching eggs with "Matilda" should not be difficult - even if you live in an area that does not have electricity. Good Luck!

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Copyright 1995-2004 by Dennis Hawkins, All Rights Reserved.