Another thread on Incubator temperature and pullet/cockerel ratio- And Pre-incubation for Storage

[rotagen]

OK, before I get the common answer that "sex is determined in the egg", let me state that I know this, what I am interested in is whether one sex can survive a particular temp better than the other, resulting in for instance more "dead in shell" male eggs.

I first read this from a source that sounded pretty legit, but darn if I can find the site again, and I think they said slightly lower temps favor the females. I incubate at 37.8 degrees or thereabouts pretty much throughout the incubation, and I would say my ratio long term is about 1:1 of course.

I read the other threads on this subject and didn't really find a definitive answer, but one person saw a huge difference with 2 incubations of 24 eggs (a decent sample size but I would say a few more repeats would be more convincing - I think 37.5C gave more pullets than the higher temp.

So I was hoping folks would chime in if they have tried this, or even better if they found a scientific paper researching the topic...

As an aside (I lost the paper of course but I could dig it up if folks really interested)... a VERY interesting paper showed that for storage at ambient temperatures for a number of days (THINK SHIPPING EGGS) that a 24 hour PRE-INCUBATION increased the hatch/survival rate tremendously. This makes good sense embryologically (to me at least) - a single cell is far more vulnerable to physical trauma than a group of say 20-40 cells.

I wish sellers would read this paper and adopt the method - it was very sound with a large sample size.

 

[Dinoroar]

I haven’t tried incubating at lower temps to effect ratios. I do remember reading sone papers on it though.

I do let shipped eggs settle a day though before I incubate. If people bring me eggs to hatch that had a long car ride I usually wait until the next morning. It seems like this is pretty widely practiced but I’d read the paper on it if you come across the link .

 

[bantamfav]

Here is a link to an article about the SPIDES treatment to improve hatchability of older eggs. Makes sense it would apply for cell death of embryos due to transport stress.
SPIDES Treatment

 

[Susan Skylark]

I’m curious about the preincubation for shipping eggs, while 20-40 cells might be more resilient to trauma than a single cell what about delay in incubation (eggs are often in the mail 5-8 days) and temperature variation (heat and cold as well as room temp are encountered depending on season and location). Can a developing embryo begin development and then just hang out for a week in extreme temps before resuming development? It may make sense if you can control both time and temp but if both those are variable as well, is there still an advantage? Sounds like we need a study, who needs a PhD?

 

[Susan Skylark]

Just did a bit of reading on preincubation, it really doesn’t look like it is a great tool for backyard chicken enthusiasts or egg shipping. Some studies find it helpful, others it is detrimental, and the gains are a one percent increase in hatchability of long term stored eggs. If you are breeding millions of chickens that could be a huge thing but for 24? There is also significant variation of what ideal preincubation is for both species, breed, and even individual set ups. Overall it probably won’t hurt anything but it probably isn’t going to do any good either unless you are a massive commercial broiler producer. Cool idea but not practical for the hobby setting.

 

[Yardmom]

I have not read the details above, but I had a hen that had a nest on top of the hay stack. My daughter kept bringing her into the pen each night, so her eggs were left uncovered every night. This went on for a week. My daughter decided to candle the eggs. There were good veins in them despite temperatures around freezing. We allowed her to hatch the chicks.