Incubating at high humidity levels and evaporation

Discussion in 'Incubating & Hatching Eggs' started by Jamie821, Dec 6, 2008.

  1. Jamie821

    Jamie821 Chillin' With My Peeps

    Sep 26, 2008
    Niota, Tennessee
    I am writing this post to hopefully help some to understand what happens when you incubate and hatch at to high humidity. First let me say I am not in any way downing anyone that says different just read please and use some common sense and maybe what I say will make sense. I am using all layman terms so as not to confuse anyone. If you disagree fine no prob but please read maybe how I say it may make you think. First if you crack a egg open you have the yolk food supply for chick the unbilical cord and what is the white of the egg. Duh huh. The whiteis where the chick floats and cushions the chick. When you set your eggs for the first eighteen days to develope the white must start to evaporate to form the air sac. This air sac has to be water free. If you incubate at higher humidities this vital evaporation will not occur thus water in air sac drowning of chick. Point being go walk in a tropicl jungle high humidity you walk through you come out wet. Follow the size of your air sac its the best indicator of humidity being to high or to low. The last three days when eggs go to hatch You want to raise your humidity just enough to not add water to the egg but to maintain the membrane from drying out when they pip and zip. If humidty is to high you are adding water to the egg through the pores in the egg shell and it accumilates in the air sac so when chick pips through membrane water present chick drowns. How may of you have hatched a couple and your next post is help chick pipped died in egg. Most times and the highest death toll on chicks is drowning from to high humidity either in incubation or during hatch. I have read and not putting anyone down people say raise your humidity to 65 and all the ones even higher like 70 and even some higher then that I cringe. Everyone means well on here and all are trying to help. I have been hatching for twenty five years and will tell you if you follow directions with the styrafoam bators you are doomed to more failure thenvictory. Cant name the hatchery but my sister in law has worked for one of the biggest egg hatcheries in the united states for years.They ship thousands of chicks every day all over the world. After following instructions and failing she finally for me went and started asking questions on their hatching techniques this I tried and could not believe the difference it made. They hatch ninety to ninety five percent of their eggs and now so do I unless shipped but even those went way up unless the post office destroyed them. I took the time to do this sorry so long because I love chickens and I know all you do too. I have heard some say that if I get two chicks I will be happy just think how happy you would be if almost all hatched. Thanks for reading just think about it and hope it helps
    1 person likes this.
  2. ginbart

    ginbart Overrun With Chickens

    Mar 9, 2008
    Bloomsburg, PA
    Well I'm saving eggs to put in my bator next week so I will try this but I have a question. What do you keep your humidity at the first 18 days? Did I miss that?
  3. swtangel321

    swtangel321 ~Crazy Egg Lady~

    Jul 11, 2008
  4. Katy

    Katy Flock Mistress

    Quote:I agree with most of what you wrote. I keep my humidity lower than a lot of people too and have close to 100% with my own eggs. I do disagree tho that that isn't the umbilical cord in the egg. It's what keeps the yolk in position...kind of like an anchor. I can't think of what it's called right now...chalazia or something like that.

    ETA: I went and looked the spelling up and I was's called the chalaza.
    Last edited: Dec 7, 2008
  5. Jamie821

    Jamie821 Chillin' With My Peeps

    Sep 26, 2008
    Niota, Tennessee
    your right katy should have reread. too long a post for a old woman like me. For the one that asked about first eighteen day humidity I keep mine around thirty five and dont add water till it drops to twenty five. I leave it at twenty five for a few hours then add about a teaspoon of water and that brings it back up to around thirty five. some areas you may need to add a little more but do it slowly as it takes a little time for the water to be warmed and absorbed into the air in the bator if you add to much to quickly it could shoot up to high
  6. Sagenovese

    Sagenovese Chillin' With My Peeps

    Mar 25, 2016
    I think you are saying that 65% is too high for Lock Down.
    But I am not sure what is the right Lock down humidity.
    35% for first 18 days. Then raise it to what?

    Thanks so much for this post as I have 4 shipped eggs under broody hen but she has been broody so long that I fear she may quit before hatch. I made a DIY styrofoam incubator for back-up just in case and so glad that I read this post!!!

    My DIY incubator is wanting to be around 70% humidity so I am taking water out based on this post. I will back it down until I find the right spot just in case my broody quits.

    Oddly, though, you mention how important the air sac is. I have one very clearly developing egg with veins and a picture perfect air sac. Another egg seems to be developing as yolk has clearly vastly increased in size though I cannot see veins at all. It has a saddle air sac. The third egg also seems to have a yolk that has expanded vastly, no veins that I can make out but based on the darkness of half the egg, I am guessing something is changing in there but that one has no foreseeable air sac. The last one is a dark brown (likely marans) egg and this one is really hard to see... not sure if I see anything... no air sac to speak of as of day 10. Any thoughts?

    These eggs are all tucked up under my broody marans who is tirelessly sitting away. Hopefully, she stays put for 11 more days!

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