Ok, what's the deal.

[mandelyn]

I set 7 eggs... 4 Cochin, 2 Spitzhauben, 1 Astralorp. All 4 Cochins hatched but one with splay leg on one limb. None of the big eggs. I just ordered Light Sussex and Wheaten Penedesenca hatching eggs to do just big eggs this time.

There HAS to be something about egg size. I can hatch the heck out of Bantams, Quail, and ducks. But never in all my small attempts have I gotten big chicken eggs to hatch. Have only ever tried 2-4 at a time though. I ordered 24.

The reason I say there is something different... because I will get 100% on Bantams and nothing out of the big eggs on day 21. I leave them until day 23 just to be sure. I broke open these last ones to see.

One Spitzhauben never started, tossed it at day 14. The other quit around day 14. The Astralorp was fully developed but never absorbed the yolk or pipped. But 100% on the cochins!! I don't get it.

Any advice or ideas? I use a Hovabator. It's always been successful for my Bantams. Now I want eating eggs so I went with standards, with 2 Bantam Cochins for fun.

Is it a temp thing? I managed 99.5 whole way through this last hatch. Do bigger eggs need more? Humidity was fine besides the time 6 days in when it went dry because my husband turned on the dehumidifier in the basement, though that crisis was solved quickly. I was thinking of aiming for a flat 100 degrees.

Or would they want less because the egg is closer to the heating element due to size? So a flat 99? Every other time was a steady 99.5 and nothing big hatched. Always fully developed but not coming out, for the most part.

Help! I have 3 days to make a new plan!

 

[Ridgerunner]

I don't know your full history of hatching but I'll mention some of my experience, all with large fowl. No bantams. I had 7 hens, 2 Delaware, 2 BA, 2 BO, and 1 Speckeld Sussex. The rooster was a SS so I could tell which chicks were from which breed after they feathered out. All of them contributed eggs for the incubator. Out of 17 that hatched, 8 were from the BA, 7 from the Delaware, and 2 from the BO. None from the Speckeld Sussex. For the next batch, out of 10 that successfully hatched, 6 were from the BA, 3 from the Delaware, and 1 BO. Again, none from the SS. I did not mark which egg came from which hen, so I cannot tell you for sure if the SS eggs ever started developing, but from the low numbers of clears, I'm pretty sure some did. But none ever made it fully through hatch.

The SS regularly lays a nice egg. I don't think it was a case of her eggs not being represented in the incubator. I did vent trim all of them, not just the BO's. I don't think fertility was an issue for any of them. I usually get bullseyes on all the eggs I check. I don't think it is a breed thing. I think that some individual hens lay eggs that are hatchable and that some lay eggs that are not all that hatchable. You can probably guess which ones I'm going to keep as replacement pullets and which hens I'm going to replace first..

If this is the only time you have tried to hatch from these large fowl hens, your one time is not enough to show a pattern. It could just be bad luck. If you have done this a few times and have a consistent pattern, then I'll submit that maybe it is not the size of the eggs but maybe something with the individual hens.

Good luck!

 

[sheila3935]

I think maybe its the eggs. I just hatched 22 RIR eggs out of 23 all are doing fine. I have never hatched bantam eggs yet anyway. I used an LG incubator and temps were the same as yours and I had some low humidities early on too.

 

[Rozzie]

Perhaps your incubator is heating unevenly. Large eggs would be exposed to a different level in the incubator. If it is higher or cooler in that area then a portion of each large egg could have a different temperature -- either over or underheated. The banty/small eggs sit down lower in the incubator and may have a different temp for hatch.

 

[Ridgerunner]

I forgot to ask. Is your Hovabator still air or forced air. In a still air the temperatures will be different based on position in the incubator, especially height, and the recommended temperatures at the top of the eggs is 101.5 dgrees F. A forced air should have the same temperatures all over the incubator (should does not always mean is) and the recommended temperature of 99.5 degrees F.

 

[mandelyn]

It's thermal air, whatever that means.

It's been any small batch of large eggs, in the past 15 years. Never an issue with Bantams, always the same type of incubator.

This time with ordered eggs (I don't maintain a rooster) I'm going with a highly recommended seller and am thinking on a slight increase in temperature.

Something is going to hatch at some point no matter how many tries it takes!

 

[Rozzie]

I think thermal air is probably referring to a still air incubator. A forced air incubator would have a fan in it. You'd hear the fan running and be able to see it when the incubator is open.

Thermal air incubators don't keep the same temperature at all levels of the egg. So, depending on how your incubator operates, it might be hotter or colder at the floor level than at the top of larger eggs. You could get a $7 reptile tank thermometer with a long wire at Petco and test it at different levels of your incubator. Just set height objects in your incubator, set the thermometer sensor on those objects and then close your incubator and turn it on. You may have a degree or two of difference. I can't say where it will be higher or lower because this would depend on your incubator. If you'll take a few days to test this out when there are no eggs in it you will probably be able to figure out what is going on with your large eggs.

 

[Ridgerunner]

As a thought, I'll give you these links. They may help. I found it interesting in the Florida one that the smaller eggs can hatch a little earliier than the larger ones. I think they may be talking about smaller eggs compared to other eggs from the same breed, not eggs that are smaller because of the differences in the breeds, but I really don't know.

Mississippi State Incubation Troubleshooting
http://www.poultry.msstate.edu/extension/pdf/troubleshooting_incubation.pdf

Florida Incubation Troubleshooting
http://edis.ifas.ufl.edu/aa204

I also think a thermal air means still air. In those, hot air rises so you can have it quite a bit warmer as you go up in elevation. The usual recommendation for a still air is that the top of the eggs be kept at 101.5* F. In a forced air, the normal recommendation is 99.5*F since the temperature should be the same throughout the incubator.