Experts, can we talk humidity and general hatching rate improvement?

[rebelcowboysnb]

I would think the shell would keep the wind from having an evaporation an cooling effect?

The wind hitting the shell is not hitting the liquid in the egg? I dont now a good way to test it?

 

[muddstopper]

think of it with the same reasoning as your humidity changeing with the amount of air exchange. One would think the shell would protect in that situation as well. The kicker is the shell is porous and allows the egg to breath. With the exchange of O2 and CO2, you also loose H2O. The more air movement, the more moisture that can be pulled from inside the egg. There is very little wind under a setting hen.

 

[rebelcowboysnb]

Still dont think so but....

I may have a way of testing this......

 

[countrychics]

as a seller and frequent buyer of shipped eggs, i have noticed an extreme drop in hatch rates this time of year...factor 1, most important is temp..i believe only fed ex ships control temp... i had many fertile eggs i shipped out hatch an awful rate due to extreme temps via usps.. secondly..best if you do not fool with eggs from say just before thanksgiving till after christmas....well after............. packages are at an all time rate of being thrown, shuffled, stacked...and well you know....so on...i had a man on ebay curse me out via email because his post man left the eggs...clearly marked with temp. warnings... at his mailbox.......also shipped eggs that arent in box small end down... and box is marked with arrows pointing this side up..almost never hatch..i suggest wrapping eggs and placing in box horizontally.... but to agree with all posts above..you actually had a great hatch rate for shipped eggs this time of season when natural fertility is also down....dana

 

[silkiechicken]

Quote:
There is a research article in poultry science from a good number of years back that delt with optimal rack spacing in commercial incubators and their effect of air speed over eggs. They concluded that there was some effect, but in the end, it came down to the percent weight loss in each egg needed to be something like 10-14% for a good hatch, regardless of the egg losing it all in the first week, or over the three weeks. If you had more airflow, it was compensated via increased air flow over the water trays meaning higher relative humidity and decreased water loss per egg. There are plenty of variables, another which was pointed out, that the internal temperature of the egg decreases with the rate of water loss.

 

[muddstopper]

I dont guess by any chance you have a link to that study?

Found it and some other good info.

http://ps.fass.org/cgi/content/full/87/9/1913
The eggshell temperature data of experiment 2 in Table 3 suggested an interaction between increasing egg weight and incubator location with respect to increasing egg temperature at E 18. This would somewhat explain the position x egg weight interaction for percentage late deads in experiment 2. Given the consistency of these particular incubators (Van Brecht et al., 2003), the significantly higher late dead embryos found in experiment 1, and the effects of increased fertility on egg temperature (French, 2002), it would be highly probable that the effects on egg temperature with respect to position and egg weight also occurred in experiment 1. Difference in air velocity was a probable explanation because it has been found to play an important role in heat transfer from eggs to their environment. With greater air velocity, more heat will be removed from the eggshell during late incubation or accumulated by the egg during early incubation. At low air velocity, egg temperature has been found to increase. Egg temperature increased with increasing egg weight in the study of Meijerhof and Lourens (1999). This could explain the position x egg weight interactions for percentage late deads as well as percentage fertile hatchability and second quality chicks because the more evident effects in experiment 1 were consistent with greater fertility (embryo heat) in the presence of similar egg mass. There have also been problems reported with chick quality from large eggs in the presence of a lower air flow in an incubator, which could be consistent with the data of experiment 1. This means that problems with embryo temperature may not only be reflected in a reduced fertile hatchability but may also influence chick quality and posthatch growth and performance. Data from a recent study by Hulet et al. (2007) found that chicks hatched from eggs with a high eggshell temperature during the last 3 d of incubation exhibited a lower BW at 44 d of age than chicks hatched from eggs with lower eggshell temperature.

http://www.lib.ncsu.edu/theses/available/etd-11062007-110540/unrestricted/etd.doc.pdf
During the early incubation period, ventilation has been shown to remove excessive
moisture from the air (Owen, 1991). However, increased air speed has not been shown to
increase water evaporation from the developing embryos (van Paemel and van Itterbeek,
1951; Romijn and Lokhorst, 1960). Increased ventilation during early incubation has also
been shown to improve initial temperature uniformity.

 

[Boggy Bottom Bantams]

Quote:
I have to fully agree with this post. If I ever run them under 55% they are all sticky and half dead by the lockdown dates.
I run 65% actually in my Sportsman and do great with them. Then again, I live in south Georgia and our air here is 80% or higher year round anyway. I've done this for 27 years now,and always have better luck on higher percentages, I know lots of folks disagree with it, but I dont see how they hatch anything under 50% for any part of the cycle.
Then I also have to agree with the post that say, it all depends on where you are and what style incubator you use. That plays a big role in it too I feel.
Also certain species, like peafowl and turkeys, need it higher than say chickens too, so lots of varialbes to figure in, that's why no 2 people will tell you exactly the same story on humidity, as a rule of thumb 50%-70% will do in most cases

 

[rebelcowboysnb]

Quote:
The way I read that is that more air speed helps with heat exchange an has no effect on evaporation.... Pretty good argument for bigger fans. Maybe turning the temp up some later in the hatch?

 

[muddstopper]

thats the way I read it to, which is why I underlined those two paragraphs. Those two studies go into a lot of detail about temp and humidity, as well as air exchange. I recommend that everybody take the time to read the entire studies and not just the cut and paste portions that I posted.

 

[duckluck]

I saw something interesting on "Modern Marvels" the other night that I had not heard anywhere before...it was a show specifically about eggs...said that the pores in eggs expand during the last few days of the hatch cycle. I didn't know this, but it also said this helps the chicks to be able to break the shell, because it weakens it. Guess this is why we run higher humidity during the last few days, because that would also mean more air can get into the shell and dry out the membrane.