Surface area exposure question

greenaus · **Posted:** Sun Aug 24, 2008 11:09 pm

I have an interesting question...I hope I can explain it well enough.

Sooner or later I might build some kind of semi-auto turning thing that holds the eggs in place and I simply turn it over or tilt it 3-5 times per day. Will it matter if the system that holds those eggs covers bits of the egg for the whole 18 days of turning?

To simplify, and this is NOT what I will be doing, let's say I put insulated "snow season" gloves on (so the turning mechanism -- my hand -- doesn't exchange anything), held an egg with only the top and bottom exposed, stood in 38 degree heat (24/7) for 18 days with a constant humidity of 60% (sounds like an uncomfortable place to live) and turned my hand back and forth 5 times per day, some of the egg will not be exposed to the air/heat until the final three days when I put it down on a non-slip mat to hatch.

Basically, how much of the surface area of the egg needs to be exposed to heat? Are problems caused by ANY part of the egg not being able to have free air exchange?

A broody hen turns the eggs regularly (apparently). We know that turning is important to keeping the developing chick (embryo) from sticking to one spot or trying to get all its nutrients from one spot. But, is it also necessary that heat is focussed on a different location and that the air exchange occurs at a different location so that the content of the egg at that location doesn't become "bad"?

The increase in air sac size during incubation assumes the air enters at that location. Does it?

Also, is it important that oxygen be available during the first 18 days?

greenaus · **Posted:** Sun Aug 24, 2008 11:12 pm

P.S. - If no-one answers or no-one can give definite answers, I may have to experiment. I don't actually NEED to hatch out my chicks, so I can make mistakes for the cause.

Egglive · **Joined:** Fri Dec 14, 2007 10:58 am **Posts:** 267

Sorry greenaus, I don't know. I would guess that the material holding the egg would be at the same temp anyway. I would be more concerned about inhibited either evaporation of moisture from the egg or absorbtion of moisture and oxygen from the air. If you experiment just keep the contact space to a minimum.

I have an E2 with the plastic trays. One way that I got caught by the holder was when I forget the date (again!) and didn't transfer the eggs down to the hatching trays. Four of the eggs in the trays are in holes that have a plastic support next to it. It's about 1cm wide and vertical against the egg. Just my luck - one chick pipped right at that point and them couldn't breath or get out. He was a little welsummer and looked perfectly healthy.

I always have way too many eggs in and just lose track of them. Yes - I know I should write on them and sometimes I do. Most of the time if I miss a date, I see a few pips and that tells me to transfer down.

greenaus · **Posted:** Mon Aug 25, 2008 8:46 am

Thanks for your input. All input is welcome.

I found this manual turner in the Photo Gallery some time ago, but like I commented there, I cracked eggs trying something like that with only mouse/snake mesh.

Maybe a little strategically placed non-slip matting will help.

I have another related question regarding the importance of the air sac end being elevated compared to the other end.

How important is this really during the first 18 days?

Broody hens don't go to that sort of trouble.

Someone recently who was incubating hadn't been told to do it and they got great hatch rates and probably didn't elevate the air sac end even during those final three days.

A really simple system of having the eggs held in place in a mesh cage which was turned over wouldn't have the air sac elevated after each/every turn.

Whatever I do has to take minimal space.

Egglive · **Joined:** Fri Dec 14, 2007 10:58 am **Posts:** 267

What about a simple frame that is moved in a push/push action. You've probably already tried that I guess. I used to have one made of wood, but you could make one out of more moisture resistant material.

greenaus · **Posted:** Mon Aug 25, 2008 5:49 pm

The only type of turning I've ever done is manual turning...with my hands.

The mesh one I began to make a few months back was abandoned when it became obvious that eggs would be cracked.

The simple push thing sounds like what "Farmer Brown" had in his incubator in an old black and white video I saw on YouTube.

http://www.youtube.com/watch?v=PYLm3SK_vRE

That is the method I've thought of the most over the last few months.

Egglive · **Joined:** Fri Dec 14, 2007 10:58 am **Posts:** 267

Yeah something like that. It looked like he pulled something and the underneath tray moved to turn the eggs. That's quite space efficient.
That's a bit different to the Belsouth100 semi-auto turn which looks like the eggs actually roll and move position slightly, instead of rolling on the same spot. The advantage of the Bellsouth one is that you don't have to open the incubator to do it, whereas the other one requires you to put your hand in (so open door). It would be better to nut out a way to do it without opening - makes it more stable.

greenaus · **Posted:** Mon Aug 25, 2008 9:30 pm

Yeah, I understand your point. But a hen gets off her eggs for a lot longer than the the time I'd have the incubator open for. Doesn't stop us all worrying abut temperature stability though.

I think we get more worked up about it than any broody hen does.

And, don't go thinking broody hens are snappier. Just ask any parent who has kids that touch the incubator. ;-)

Egglive · **Joined:** Fri Dec 14, 2007 10:58 am **Posts:** 267

My OH isn't even allowed to touch the incubator!

I get what you say about the hen getting off the eggs. I open my incubator door whenever I like, especially when goose eggs are in there so I can spray etc. My E2 gets back to temp & humidity really quickly. When I used to have a Bellsouth - whole different story - the swings & roundabouts used to start up all over again. Same deal when I had a Little Giant - that was even worse. I think it's all about your machine, some are good and some are touchy.

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