Humidity - What is too high during the first 18 days?

Discussion in 'Incubating & Hatching Eggs' started by CollegiateChicken, Apr 17, 2012.

  1. CollegiateChicken

    CollegiateChicken Out Of The Brooder

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    Apr 19, 2011
    I've just finished a DIY incubator from instructions I got here: http://www.instructables.com/id/How-to-make-a-styrofoam-quotstill-airquot-egg-/.

    My problem is, while the temperature is remaining stable at 99-100 degrees, with occasional jumps up to 101, the humidity is ranging from 55% to even 70%! I tried putting eggs in after it had stabilized at around 54% humidity, and it immediately jumped up. The incubator is less than a cubic foot, about 9inx9inx9in. I had a dish of water at first, but the humidity stayed too high.

    My question is: Does the humidity have to stay below 70% during the first 18 days of incubation, or does it matter? I imagine in regions where the relative humidity is much higher, such as in the southern US, it would be hard to keep it lower, but somehow broody hens still manage outdoors! If I have to add more ventilation holes, that's fine. I'm just worried I'll have to fiddle with the thermostat all over again to compensate for any loss of heat. Any help is appreciated!
     
  2. When I got my hovabator, I contacted the makers about "RELATIVE HUMIDITY" since I can't see the water pan when the turners are full of eggs. What they told me is for the first 18 days, the relative humidity should be between 58 - 65% humidity. If your humidity is too high, your chicks could show leg developmental problems and they could also get oomphalitis (sp?) otherwise known as mushy chick disease.

    Days 18 - 21 should be 65 - 70%.

    I use a little digital hygrometer in my incubator to read the relative humidity, I don't mess with wet bulb/dry bulb... blah blah blah... sorry.

    The digital thing is much easier.

    Even with that, when I lived in CA I kept the vents open on my incubator but now I live in the high desert and I have to keep the vent closed just to maintain the humidity level for 3-4 days! Its VERY dry here. In the south, they would probably use less water and keep the vents open.
     
    Last edited: Apr 17, 2012
  3. CollegiateChicken

    CollegiateChicken Out Of The Brooder

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    That's really helpful! I've been looking through a lot of threads on humidity, but everybody is concerned with low humidity, instead of too high. I'll make sure to keep all the vents open.

    I may just decide to hatch fewer eggs. I was trying for a dozen, but that made the humidity spike too high. Maybe 6 or 8 instead. Thanks!
     
  4. Arielle

    Arielle Chicken Obsessed

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    I use the dry hatch method as the real concern is how well the air cellls develop--Many charts available to compare eggs during candling to a picture. This helps to determine if the humidity is to high or not enough in the incubator. A fan also increases the air movement and effects the air cell development.

    Diagrams of air cells, duck and chicken:

    http://www.poultryconnection.com/quackers/aircell.html



    Stryofoam really keeps in the moisture. Did you get ventilation holes poked into the lower area and the top?

    I do not put any water in my incubator until lockdown; however, in dry areas like the desert and in the eaerly winterwith my wood stove going I have added water.



    It's all about the increasing size of the aircell over the days until lockdown.

    Hope this helps with the understanding of the relationship between aircells and humidity and air flow.
     
    Last edited: Apr 17, 2012
  5. A.T. Hagan

    A.T. Hagan Don't Panic

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    Try reducing the surface area of the water dish you are using or use a smaller dish. By this I don't mean using a shallower container but one that exposes less of the water surface to the air. Humidity is strongly affected by the surface area of the water within the incubator.

    The plastic container I'm currently using in my cabinet incubator is too large in surface area for the humidity range that I want for days 1-18 incubating. To decrease the water surface I floated an upside down plastic lid from a butter tub. Worked great. Less surface area equated to less humidity. When I need more for the days 19-21 hatching period I took the butter tub lid out and the humidity increased.

    What range you should keep the day 1-18 humidity in can vary with the region of the country you are in and your local conditions. I've known some who got good hatches who kept their humidity at 80%+ but they lived at a fairly high altitude in an arid climate. Here in Florida in my air conditioned home I prefer to keep my humidity in the 45-50% range for days 1-18 and in the 60-65% range for days 19-21.
     
  6. CollegiateChicken

    CollegiateChicken Out Of The Brooder

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    Apr 19, 2011
    I think I found the problem. I had spilled some water when removing the tray of water, and it was in the corners at the bottom of the bator. I left it running overnight without eggs, and it is now currently at 35% humidity and has stayed at that level since this morning. I think the spilled water finally evaporated. So now, I'm going to keep it running overnight and on until tomorrow, without any tray of water, to see where it stays. Hopefully when I put the eggs in, it will stay below 50%. Thanks for the advice on aircells!
     
  7. Arielle,

    Regarding using the dry hatch method... how do you do that? Do you use a fan and no water? Or no fan and no water either?

    I ask because I'm having problems this year that I'm suspicious might be due entirely to humidity. I've never had these problems before but this year its rampant! Leg problems and unhealed navels! I'm keeping my humidity according to what the manufacturer told me but still having trouble. I've had ten hens go broody this year and not one of them has had regular humidity like in the incubator. I think the relative humidity here is like 9%. VERY LOW. With my broodies, I only put a little water in the nest on day 18 or 19 to increase humidity under the hen. They have all hatched out fine... no problems whatsoever.

    Can you tell me about this dry method please? I'm sure my hens are using it and they don't have fans either.
     
  8. Arielle

    Arielle Chicken Obsessed

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    Hopeful the OP will find this useful, I apologize for hijacking the thread.


    Not all incubators are created equal. A small stryofoam type is managed much differently that a huge wooden incubator.

    THe small styrofoam incubators need a stable room temperature to start,

    Humidity--when I started incubating I had already figured out this was the key to getting chicks to hatch. THey would grow, then die during lockdown. Humidity is the biggest contributor to chicks successfully hatching. Most people can manage the correct temp, but humidity management gets overlooked.

    Dry hatching is when little or no added water is placed in the incubator during the first 18 days. Styrofoam incubators hold in the moisture. Eggs need to loose about 13% of their weight in water; I have a flashlight , not a gram scale, so I candle and compare to the diagram. If the aircell is too small at day 18, the chick is too swelled up with water to wriggle to pip and zip. It also needs to be dry around him because he becomes air breathing inside the egg and any excess moisture causes drowning. ALso egg can loose too much moisture and that is detrimental to the chick as well.

    Ventilation is very important. THis is a living creature. The vascular system lines the entire inside of the egg. It picks up oxygen and exchanges other waste gases. Moisture will leave the egg if the humidity is low and good ventilation removes the moist air.

    50% RH in the room the incubator is in is generally recommended. THis isn't always the case depending on where you are. You can adjust the moisture levels in your incubator using air conditioning or adding water into the incubator.

    30% is the average INSIDE the incubator that works for me. If it dips to 19 I leave it alone. Another day it might be at 35%. THE MOST IMPORTANT GAGE IS TRACKING THE AIR CELL DEVELOPMENT or doing the weighing method.


    Did you punch air hole in the bottom of the incubator? Or low on the sides? Are they blocked? Did air holes get punched at the top? As warm air rises it exits the air holes and the negative pressure pulls fresh air into the incubator. When the warm air leaves it also takes moisture with it and helps dry the egg. A fan increases the rate that the air leaves the incubator, if there are holes.

    A fan is not necessary. I does help with more even temperatures thru out the incubator in a large incubator.

    Chew on this info. and let me know if you have a question.


    Diagrams of air cells, duck and chicken:

    http://www.poultryconnection.com/quackers/aircell.html
     

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