Randomly appeared blood rings, what caused it ?

[CuriousAmateur]

For some context, our bantam was broody last month and now has 3 lively chicks. She had a clutch of around 11 because of inconsistent checking and due to other chickens sitting on her to lay their eggs. (There are other nest boxes !) 4 were closer to lockdown and the other 4 less than 7 days old or so.

To feed the needs of her recently born chicks, she hopped off the clutch and I realized about an hour later that she hadn't returned. It's winter here and while it doesn't snow, the eggs felt colder than lukewarm. Quickly put them in the incubator and it's been 3 or 4 days since then.

Today the incubator smelled off, candled all the eggs and 2 of them had clear blood rings. Veins had dispersed. Another wasn't moving, and I could see the blood ring forming like a dotted circle. They were all next to each other, so I removed them and tossed them. But now I have questions so that I can prevent this.

What caused this ? Was it the different conditions as to what the eggs were used to ? I am doing a 'dry hatch' where the RH is just below 40ish%. Were they more inclined to be quitters because they had been in the cold for an hour ? Is it like immunity systems in the fact that it was weakened due to being in the cold ? Can blood rings spread ? They were next to each other and the smell kind of rubbed off.

Please be as specific as possible, this is my first batch and now I'm down to 8 eggs. The surviving 1 out of the 4 is on about day 5 or so while my current batch are on day 10 and 11. Thank you for reading !

 

[JaffaDuck]

@SilverBirds

 

[SilverBirds]

Blood rings form after an embryo dies. They don't spread or influence the death of other eggs unless the dead one explodes or leaks, releasing the bacteria out and into or onto the other eggs. When multiple eggs die, it's usually caused by improper temperatures or humidity, or, if they are from the same parents, poor nutrition or genes from the parent stock. In your case, the temperature is likely the culprit. Eggs aren't very hardy in the early stages, so their being in the cold may very well have terminated the embryos. Of course, moving to the incubator could also have killed them if the babies were weak. The other thing I can think of that could have caused them to die is overshaking. It's possible you were too rough when transporting the eggs from the nest to the incubator.

 

[CuriousAmateur]

Blood rings form after an embryo dies. They don't spread or influence the death of other eggs unless the dead one explodes or leaks, releasing the bacteria out and into or onto the other eggs. When multiple eggs die, it's usually caused by improper temperatures or humidity, or, if they are from the same parents, poor nutrition or genes from the parent stock. In your case, the temperature is likely the culprit. Eggs aren't very hardy in the early stages, so their being in the cold may very well have terminated the embryos. Of course, moving to the incubator could also have killed them if the babies were weak. The other thing I can think of that could have caused them to die is overshaking. It's possible you were too rough when transporting the eggs from the nest to the incubator.

Thank you ! I was worried that my current batch would end up bad but they seem fine. I think I was careful enough with the eggs, though I did have to travel through a flight of stairs. I might've put them in too early without allowing them to come to room temperature. Least I'll know for my next batch, thanks again !