Draw down?

Discussion in 'Incubating & Hatching Eggs' started by Apriljc, Apr 25, 2011.

  1. Apriljc

    Apriljc Chillin' With My Peeps

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    Apr 14, 2011
    What physiological changes cause draw down? Is it the reduction in contents ad the chick swallows the fluid and absorbs the yolk?
     
  2. Ridgerunner

    Ridgerunner Chicken Obsessed

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    Do you mean why the air sac gets larger? That is because the moisture in the egg evaporates through the porous shell. That is why humidity during incubation is important. The humidity in the incubator controls how much moisture is lost through the shell.
     
  3. Apriljc

    Apriljc Chillin' With My Peeps

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    Apr 14, 2011
    Quote:I ask because I have one egg that is drawing down very well and one that is not....the chick IS alive--I can see it move. It seems like it has always been behind the other egg (I am riding on the success of only TWO eggs!)
     
  4. HHandbasket

    HHandbasket The Chickeneer

    Quote:I, too, thought that was the case, but another thing that also causes it is the eggs being old and sitting around a while before being set.

    With our most recent hatch, we did have a massive dip in humidity for about 24 hours when we weren't home. ALL the shipped eggs I got from one certain breeder developed large, irregular air sacs that took up 1/3 to 1/2 of the inside of the eggs & killed the developing chicks/embryos inside. If it was caused by the humidity drop, ALL the eggs would have had the irregular air sacs. But they didn't... only the ones from one breeder that I had shipped in. (Had eggs from 3 different breeders in the same incubator at the same time.)

    On doing further research, I've discovered one of the things that can cause that is that the eggs may have sat around in low humidity for several days, even a week or more, before being shipped. I thought it was caused by the eggs being jostled in shipment, but apparently that most often causes detachment of the membrane in which NO air sac can form, rather than a large sac that takes up half the space inside the egg. It is more likely the eggs are old and were not properly stored prior to setting.

    Old eggs will draw down regardless of humidity, but I am not an expert. That is only what I have read and been told by others.
     
    Last edited: Apr 25, 2011
  5. Apriljc

    Apriljc Chillin' With My Peeps

    198
    1
    101
    Apr 14, 2011
    Quote:I, too, thought that was the case, but another thing that also causes it is the eggs being old and sitting around a while before being set.

    With our most recent hatch, we did have a massive dip in humidity for about 24 hours when we weren't home. ALL the shipped eggs I got from one certain breeder developed large, irregular air sacs that took up 1/3 to 1/2 of the inside of the eggs & killed the developing chicks/embryos inside. If it was caused by the humidity drop, ALL the eggs would have had the irregular air sacs. But they didn't... only the ones from one breeder that I had shipped in. (Had eggs from 3 different breeders in the same incubator at the same time.)

    On doing further research, I've discovered one of the things that can cause that is that the eggs may have sat around in low humidity for several days, even a week or more, before being shipped. I thought it was caused by the eggs being jostled in shipment, but apparently that most often causes detachment of the membrane in which NO air sac can form, rather than a large sac that takes up half the space inside the egg. It is more likely the eggs are old and were not properly stored prior to setting.

    Old eggs will draw down regardless of humidity, but I am not an expert. That is only what I have read and been told by others.

    Thanks for your thoughtful response. I set these eggs they same day they were collected from the hen. Some one told me they thought my humidity was too high during the incubation and so they didn't loose enough fluid. BUT there is a dramatic difference between the two eggs.

    However, these two eggs have always been different from one another. For example. I knew the "better" egg was fertile and growing a few days before the second one....

    Oh, I am just stressing...I want so much for them to hatch and be happy
     

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