Question about turning eggs

Actually broody hens stop turning eggs once they feel them moving. I was even under the impression they don't leave the nest at all at that point. Never noticed one out of coop last day or so of a hatch but could be wrong.

With our imitation of this we stop turning prior to hatching also. What's been learned through experimentation as much as by repeatable accidents is we can stop turning at day 14 or 15 without ill effect on hatching rates. With auto turners there can be ill effect allowing it to continue turning as the chicks are popping out.

What I take home from this is we generally up the humidity day 18 or 19 in preparation of hatching. We do it a bit early as some times they hatch early and want the humidity up. We also want to take out the turner at some point. Might as well do it all at once and lets have a rule of thumb day to do these things. Day 18 works well for that. I do it before bed day 18 or early day 19.

 

I've also read that we stop turning so the chick can get into proper pipping position.

 

I stop turning at the end of day 13 because the Cobb development charts says that day 14 ish is when chicks make their turn toward the air cell end. Eggs do not need to be turned after two weeks because they can move themselves and there is no danger of "sticking" to the side causing development problems. My last hatch (20 chicks) I had zero upside malepositioned chicks. I didn't have a problem over all with malepositioned, but it wasn't common to have at least one per hatch. I feel that the less turning at time of the chick turning can only help them complete that process.

I believe that people generally choose day 18 because this is "lockdown" for a majority and the greater emphasis on hands off and not opening the bator, limits the ability to turn after lockdown. So, everything is done at that time. I myself don't subscribe to the hands off theory, but I do raise my humidity at day 18.