How Correct Humidity can Improve Your Incubation and Hatch Rate

20190528_163125Humidity in the incubator has always been a tricky thing.  Too much of it or too little of it can ruin your hatch rate.  Humidity starts out at one percentage but then needs to be raised at just the right point in order for a successful hatch.  This can leave some people scratching their heads at just how to accomplish this feat.

Air can absorb water. This water vapor is a gas.  Water vapor in the air can range from none to the full maximum which air can hold.  We call this saturation. This full maximum can increase as the temperature rises.

When talking about humidity in the incubator we are usually discussing the Relative Humidity.  This is expressed as a percentage. It is a measure of the amount of water vapor in the air compared with the maximum that could be absorbed at that temperature.  If the Relative Humidity level is 50% that means that the air contains half of its maximum possible water vapor capacity.

Most people (unless they practice dry incubation) shoot for 40-50% for the first 18 days of incubation and then raise it to 65-75% for the final three days of hatching.  In general, slightly lower humidity is better than too high of humidity during incubation.

Start by following the manufacturers recommendations for humidity and temperature for your individual incubator.  Then for future hatches you can tweak the numbers and make minor adjustments for what works best for you.

Many factors affect humidity such as : Egg size (the smaller the egg, the greater the moisture loss.), Porous shell (which increases with a hen’s age), elevation, egg storage length and conditions, weather, incubation temperature, air speed and shell thickness (which decreases with hen’s age. Thinner shells require higher humidity.)

Egg shells are porous and they allow water to pass through.  The amount of water that an egg loses during incubation is important and is determined by the humidity levels in the incubator.

If you set your eggs with the pointy side down, you will notice an airspace at the top rounded part of the egg when you candle it.  Water is lost through the shell gradually and is replaced by air which is also drawn through the shell.  This airspace gradually increases in size.  The greater the water loss, the larger the airspace.

This airspace is critical to the chick. It is the first air that the chick breathes and is needed in order for the chick to move into the correct position for hatching.

If the humidity has been too high during incubation, the egg will have lost too little water and the air cell will be small.  This will cause the chick to have trouble breathing and will have trouble breaking out of the shell.  Often you will see the chick’s beak protruding out of the shell. The bird is stuck and unable to zip around the shell and will not be able to hatch.

If the incubation humidity has been too low there will be very large air spaces.  The chicks are often small and weak and will have trouble cracking the shell and hatching.

Monitoring air cells when you candle will also let you know if your incubator is maintaining the correct humidity.  This chart shows you what your air cells should look like as the egg loses water. Use a pencil to draw the outline of the eggs air cell every time you candle.


During incubation, you can control humidity through the use of vents to monitor the amount of fresh air entering the incubator.  The more fresh air entering, the lower the humidity.  There are also pans of water that can be added to increase the humidity or troughs at the bottom of the incubator that can be filled with water.  Covering the pans with foil will decrease the water surface area.  It is not how deep the water is but the amount of surface area on top of the water that determines how much water will evaporate into the air.

During the last three days of hatching, you will need to up the humidity in the incubator/hatcher.  Add more water surface through the use of pans, troughs and sponges, humidity pads or wick pads. This is where a good hygrometer will serve you well.  Use it to keep track of where your humidity is at.

You can also monitor humidity during incubation by weighing the eggs.  Most eggs need to loose 13% to 15% of their weight from the time of setting eggs until hatching.  Weigh them every 5 days and chart their weight. Use this chart as an example.  Adjust your humidity if your eggs are not losing enough weight or are losing it too quickly.


I use Hovabator incubators for the first 18 days of egg incubation.  I only fill the first trough with water and remove the red vent plugs so that the eggs get plenty of fresh air.  I end up putting additional water in that first trough about every three days.  It will dry out if you don’t add more water.  Depending on the time of year I am at around 50% for the first 18 days.  Candling on day 18 should show an air cell that takes up about 1/3 o

I use a Brinsea Octagon for the last three days of hatching.  I increase the humidity by placing two absorbent shop paper towels so that they hang into the troughs and up under where the eggs will sit. When the water is poured into the trough, it will wick up making a large wet surface area. This will increase humidity in the hatcher.


I begin by only filling one of the troughs with water and I place the basket that will hold the eggs on top.  I then cut out little holders for the eggs made from paper egg cartons.


I place the eggs in their holders and leave the hygrometer inside where I can see it through the window. Humidity is around 66% at this time.  The hatcher stays this way for day 18 and day 19. On the morning of day 20, I fill the 2nd trough with water and begin lock down.  I like to wait until I see the first egg pip before I add water to the second trough.  This will cause the humidity to go up into the 70s %. I keep the vents open slightly to let some fresh air in, but keep most of humidity trapped .  Once the eggs start hatching I try to delay lifting the lid for as long as possible. Once the lid is lifted it is hard to keep the humidity up for hatching. It can cause the membrane to dry out and make it harder for the chicks to break through. If I need to open the lid I make sure to spray the inside walls with warm water to bump the humidity up faster. I have found that this method works very well for experiencing wonderful hatch rates.

For tips and tricks for raising outstanding silkies check out our Chicken Learning Center at .  VJP Poultry is an NPIP and state inspected hatchery located 30 miles north of St. Paul.  We hatch out silkies all year long so we always have stock available.  Like us on Facebook to get weekly updates on what we currently have for sale.

Victoria J. Peterson



January Improvement Project – Chick Windows at VJP Poultry – 1/21/17

20170107_171441    We are always trying to think of ways to improve how we do things at VJP Poultry. We want to be able to complete chores  more efficiently . Time is a factor and it is important that we look for ways to do things faster and better.

If you have been here to visit, you know that I keep my silkie chicks in dog kennels or crates that are split in half. A wooden door was created in the front so that the baby chicks would not escape or fall to the ground. This door idea worked great but I knew that it could be improved.

The major difficulty was that you couldn’t look inside to see the chicks. We love having children come and visit VJP Poultry but they, being small, always had difficulty seeing into the pens. Their parents would often need to lift them up so that they could see into the crate.  When we moved the pens up higher, I couldn’t see in there as well.

I asked my husband, Dennis, to create windows in the front of the door. In the space of one afternoon he was able to create “chick windows” for me.

After measuring, he first used a circular saw to create openings in the door frame. Since each of the dog kennels were different sized, the door frames were all different as well.

Next he cut hardware cloth to fit the openings with some overlap. He used tin snips which easily cut through the wire cloth.

He then stapled the hardware cloth onto the wooden frame using a staple gun. Lastly, he used a body hammer to smooth any raised staples or wire edges.

I couldn’t be happier with how they turned out. Not only can children and adults see clearly into the pens, but there are other added benefits as well.

Ventilation and air circulation is now improved. During the summer it can become very hot in the chick room, but these new windows can help the chicks stay cooler by not trapping hot air in their pens.

It’s a thrill to have improvements made in your chicken care routine. Everyone benefits – even the baby chicks. They get to look out their windows and watch the world go by until they move on to their new home.

For tips and tricks for raising outstanding silkies check out our Chicken Learning Center at .  VJP Poultry is an NPIP and state inspected hatchery located 30 miles north of St. Paul.  We hatch out silkies all year long so we always have stock available.  Like us on Facebook to get weekly updates on what we currently have for sale.

Victoria J. Peterson



Silkies For Sale – 12/27/2016

Heat Lamp Use at VJP Poultry – 12/20/16

20161123_120428    Now that the weather is getting colder, I have a lot of VJP Poultry customers asking me about using heat lamps in their coops. People are concerned that their silkies will not be able to stand the cold of a Minnesota winter.

My use of heat lamps has changed dramatically since I started raising silkies seven years ago.  I used to worry that my silkies would die from exposure. I had 250 Watt heat lamp bulbs hanging in every color pen the entire winter. Some even had two hanging in them.  My electric bill was crazy. I kept the windows open only a crack and tried to raise the temps as high as I could inside.

After seven years of experience , I now rarely turn on the heat lamps in my outside coops. The silkies are fine. They actually are very winter hardy. They have a small comb so you don’t need to deal with frostbite issues. They aren’t fond of snow but they do love to go out into their runs no matter what the temperature. What is cold for a human is not cold for them. Think about all of the woodland birds. They do just fine in the cold Minnesota winter.

I have one 250 Watt heat lamp above each waterer just in case it gets really cold. I did have them all on during the spell of -40 windchill. They shouldn’t be thought of as a way to heat an entire room. They only heat what is directly below them. If it gets to be around -10 I will flip the heat lamps on. My waterers are heated a different way (from below) so I don’t need the heat lamps unless it is super cold and the water is staying frozen.

I do use heat lamps in my baby chick room. I like to use the lower 125 watt bulbs. They are not as hot and not as expensive to run. I will use a heat lamp over the newborns and the one week olds  I don’t always use it over the two week old, but I could if I needed to. The chicks are in a small room off of my garage. The room is not heated with central air, so I also use a standing space heater to keep the entire room warm during January.

I am very aware that heat lamps must be hung securely. I use chains and wire so I can adjust the distance down to the brooder. I do not rely on the clamps that come with them. Heat lamps that are not secure and fall can easily start a fire. Make sure that the hoods are wiped clean of dust and that you also blow out the outlets with an air hose.

Heat lamp bulbs gradually become less strong the longer you have used them.  You are still paying for the same amount of electricity from the 250 Watt  bulb, but you are not receiving the same amount of heat the longer you continue to use it. When I feel that its not as strong anymore, I generally switch it out for a new bulb.  I don’t want the surprise of it burning out when I really need it over newborn chicks. The 125 Watt bulbs are harder to find so we order ours online.

Remember, it is not the lack of heat that can cause issues with silkies in the winter. It is the moisture present in the coop. If you are seeing frost on your doors or walls, it is a sign that there is too much moisture and not enough ventilation.  Open the windows, but keep the drafts off of the sleeping birds. I use pillow cases stuffed with old T-shirts and place them in front of the pop holes to block the drafts on the floor.

Electricity from heat lamps can be costly. One 250 Watt heat lamp costs about 90 cents a day to run. Add a space heater and that would be an additional $1.80 a day to run.

At VJP Poultry, we use heat lamps as sparingly as possible. They are necessary for young chicks in the first few weeks of life. Make sure they are hanging securely and change out the bulbs when they start losing their heat. They can be a useful part of your breeding program.

An alternative to heat lamps brooder heat plates. There is less of a chance of fire with these.  You can also use the sweeter heaters that are hung from a chain above the chicks. This would be a more secure way of doing it.

For tips and tricks for raising outstanding silkies check out our Chicken Learning Center at .  VJP Poultry is an NPIP and state inspected hatchery located 30 miles north of St. Paul.  We hatch out silkies all year long so we always have stock available.  Like us on Facebook to get weekly updates on what we currently have for sale.

Victoria J. Peterson

VJP Poultry newborns 4