Which End is Up

[Schroeder]

I am setting some eggs that are so perfectly oval shaped I can't tell the large end from the small.  Any advice as to how I go about incubating them?
Duane

[Mike Gilbert]

That is one reason we have a provision for that defect in our egg contest rules.    If you can incubate them laying on their side, do that.  Or you could try pre-candling them to see which end the air sac is located on.

[Russ Blair]

I have always candled them like Mike said. Granted in a perfect world I would not set them, preferring better shaped ones instead. Always seems the best ones lay the worst shaped eggs lol.

[Schroeder]

Thanks guys.  I candled them and think I have them all correct.  Safe to assume egg shape is mostly determined by the male?

[Mike Gilbert]

Thanks guys.  I candled them and think I have them all correct.  Safe to assume egg shape is mostly determined by the male?

Duane, I never really considered that.   Does anyone know for sure?

[John W Blehm]

Thanks guys.  I candled them and think I have them all correct.  Safe to assume egg shape is mostly determined by the male?

Duane,

I've never heard anything about egg shape and genes.  Why do you assume it is sex-linked?  I guess if you lonely kept cockerels from the pointy eggs and their pullet daughters laid mostly pointy eggs I would say you may be right. 
I guess there is an old wives tale that pointy shells produce cockerels.  Commercial hatcheries try to only set nice oval (egg) shaped eggs and still get about a 50/50 hatch of pullets and cockerels.

[Tailfeathers]

I don't have that problem with my Am's but I've got Barnevelders that lay an almost perfectly round egg and there is no way I can tell sometimes.  Candling always reveals the aircell.  Since the Am eggs are easier to candle, I imagine it's the same with your eggs.

I do not know with any degree of certainty whatsoever about who contributes to egg shape but my guess would be the female has the greater influence since it is her system that gives the egg it's shape.  I would also be more inclined to believe that is the case because of my breeding.  Using the same male on different females has produced offspring with egg shape the same as their mother in both my Am's and my Barnies.

Duane, just FYI, I sent you an email a couple days ago.  Did ya get it?

[Schroeder]

I've never heard anything about egg shape and genes.  Why do you assume it is sex-linked? 

I thought the male's egg color is more important than the female and therefore egg shape too.

Royce: Having issues sending you photos. I just tried again. Let me know if you get it.

[John W Blehm]

I've never heard anything about egg shape and genes.  Why do you assume it is sex-linked? 

I thought the male's egg color is more important than the female and therefore egg shape too.

I believe the genes for shell color are contributed equally by the sire and dam to their offspring.  This is why some of us have written about the importance of using males from the bluest eggs in breeding pens rather than just selecting the bluest eggs to set.
Torpedo shaped eggs could be caused by several things, including genetics.  The UK site The Chicken Vet talks about shell quality. 

[Beth Curran]

This is an interesting topic - I have several that lay round or squarish eggs that are hard to figure out. Those are usually the ones with thick shells that are hard to candle, too. Not sure if there's a connection or just Murphy's Law...

[Tailfeathers]

Beth, I've found the shells that are more porous have been the worst hatching and often get blood rings.  Can't really speak to "thickness" as I've not paid any attention to that but will have to remember to look in the future.

[John W Blehm]

I'm always pushing for uniformity in chick phenotype and feel it is needed to achieve uniformity in mature standard birds.  Uniformity in eggs is important too, but probably more for hatchability.  Some BIG hatcheries need good egg shaped eggs that can be picked up from the broad ends with their suction devices to transport them from storage tray to setting trays. 
Bud from McMurray Hatchery told me that they average 74% hatches from all eggs incubated (no deduction for infertile eggs).  Like most hatcheries they buy their Cornish/Rock meat bird eggs.  He said when the eggs come in and they see many oversized eggs they know they'll have a poor hatch and reduce their expected hatch to 60%. 
In my old book "A GUIDGE TO BETTER HATCHING", by Janet Stromberg, she has a section on Selection of the Hatching Egg.  She says "Egg shape is largely an inherited characteristic" and "The porosity of the shell determines the rate of moisture loss during storage and incubation".  I've had my copy of this little book for about 40 years and although I hadn't opened it in years, it is well worn from those early years.  I talked to her a few years ago and believe her son updated the book.

[Tailfeathers]

Thank would make sense, John, and it goes with what I've seen.  I also think it only stands to reason that the more porous are more susceptible to bacteria invasion.

[Suki]

How would you know how porous a shell is?

[Mike Gilbert]

By a rough surface, usually worse on one end.   You can see it very well with a magnifying glass.   It's why I always used one when judging eggs at our national meets.