physiological reasoning behind lockdown?

[williamsl77]

What is the physiological reasoning for lockdown? I have read that on Day 18, stop turning, raise humidity, and don't open incubator, which I have done. I have also read in other places that you don't need to raise humidity until you see first pip. Purpose of raising humidity is to prevent shrink wrap, which I understand. Makes sense that raising humidity at first pip (perhaps by tube in vent rather than opening incubator) would be ok. No rushes of cold air. I understand not opening incubator after pipping has started.

That being said, I have lost fully developed chicks on every hatch I've had so far. I think I have been too cautious with the temperature and keeping it just a little too low, so that is one correction I've made. But I feel like if I understood the physiological reason for lockdown a little more, maybe I could trouble shoot more.

Another thought I had was about ventilation... especially when you don't open the incubator for several days in a row. Are they using up their oxygen? I have only one vent on my incubator and I keep it open.

Thanks!!

 

[Pele]

Good questions, and pretty much the same concerns that I had with my first hatch (which is completing today! woohoo!)

From what I've read, the chick starts trying to position itself for internal pipping (breaking into the aircell and starting to breathe) on day 18. Turning the egg may actually hinder it's progress to do so, since it literally has to turn around in the egg to face towards the aircell. Just thinking about having to turn around in a tight space while it rotates makes me seasick.

Also, it's crucial at this point that humidity be maintained, and depending on your location, opening the incubator to turn will lose you precious humidity and temperature.

And lastly, until an external pip forms, it's a guessing game to know where the chick will be coming out. The last thing you want happening is a chick working for hours to pip, and then you unknowingly rotate the egg so that the potential pip is pressed against the floor. Hatching takes massive amounts of energy, and is not something they can just do-over if their first pip puts them against an umovable surface with no access to oxygen.

Hope that helps to explain it! And I'll send good hope vibes for the success of your next hatch!

 

[williamsl77]

Thanks for your thoughts, Pele... what is critical about keeping humidity high prior to external pipping?

 

[kathyinmo]

Maybe the links in my signature would answer your question.

 

[quintinp]

In those last 3 days, the humidity is raised, because if the humidity is at 40%, and you see a pip, you are probably already too late to bring the humidity up. I think the 3 day thing is to let the incubator humidity remain at a constant, and stabilize to a certain percent. As for the turning, I am guessing that, because in most of the old cabinet incubators, and the big commercial incubators, the eggs are tilted. And they are put in a hatcher on their side to hatch. In those last 3 days the chick is repositioning itself to be able to hatch. I can take a guess, and say that the turning wouldn't be beneficial for the chick if it was trying to reposition itself.