Fully formed chicks in eggs under 2 hens never hatched.

[Nonnapoo]

The death of fully formed chicks is distinct from early embryonic death, most of whose causes ChickenCanoe listed. It sounds like your chicks were late embryo mortality (within the last 3 days before expected hatch), aka dead in shell (abbreviated DIS). Causes for this are typically the chick didn't get in the right position to hatch, didn't transition to breathing air properly, didn't absorb the yolk properly, or wasn't strong enough to break through the shell - if the shells are relatively thick, this is more likely to explain a high DIS rate than the other reasons which are more idiosyncratic and typically apply to a only small percentage of hatching eggs.

If there was a lethal spike up or down in temperature or humidity, one would expect all the eggs to fail, not just most of them (though you don't say how many eggs were set in either case), but they are potential causes of late stage mortality too.

Great information! Thanks so much.

 

[Nonnapoo]

We feed Kalmbach's Flock Maker to every bird here, from day old to old.

It's 20% protein and silkies do better on it. It's lower in calcium, so I put a dish of oyster shell in the coop and in the breeder pens. Don't let young chicks have access to the oyster shell though. I believe I have three of those six a month old now, suffering from calcium toxicity.

Thank you.

 

[ChickenCanoe]

Thanks! I didn't realize this.

To further elaborate, there are many types of feed for various stages of life. Only Layer has approximately 4% calcium. Virtually all others are about 1%. That is adequate for growth and body functions except when a hen is actively laying and more is needed in feed or supplements to replace the calcium used from the medullary bone each time a shell is built in the uterus. There are also feeds like feather fixer that is for during molt with more protein to build a new winter coat. Since molting birds normally don't lay eggs but others in the flock may still be laying, that feed I recall is about 2 1/2 % calcium. Something else to consider is that since not all hens lay with the same frequency, 4% calcium may be insufficient for extremely prolific birds like Leghorns or RIRs and still excessive for poor layers. For this reason, some people don't use layer feed but rather an all flock type feed and offer oyster shell or mineral calcium carbonate in a separate container so the hen can choose how much to consume. This works surprisingly well.

 

[BigBlueHen53]

Don't let young chicks have access to the oyster shell though. I believe I have three of those six a month old now, suffering from calcium toxicity.

what are the signs of calcium toxicity? We integrate our chicks into the main flock at about 8 weeks and there is OS in the coop so of course they would have access to it. I've always understood that only laying hens would take advantage of it while non-layers might sample it but generally will leave it alone.

 

[Debbie292d]

what are the signs of calcium toxicity? We integrate our chicks into the main flock at about 8 weeks and there is OS in the coop so of course they would have access to it. I've always understood that only laying hens would take advantage of it while non-layers might sample it but generally will leave it alone.

This is not definitive, but I ruled out vitamin deficiency in chicks who are penned with parents and get only flock maker, vitamin water, occasional scrambled eggs, and occasional Henhouse Reserve scratch for the adults. There was a feeder of oyster shell out there.

Of six chicks, I saw one floundering so brought it in the house. One leg went one way, one leg went the other. Hours later I went out there and there's another doing the same thing. The next day, one suddenly has cross beak. There is one of the six that has been in the house after one week out there for a separate issue, that has no other issues. There is one chick still out there, no issues. The first one I brought in seized and died.

The other two with the same leg issues seem to be coming around very slowly. https://www.backyardchickens.com/threads/disabled-chickens-forum.1594570/post-28088937