Blood rings?

[chipens]

Ive just candled my eggs in the bator (day 7) and have lots of blood rings , out of 12, 5 have blood rings, 3 were not fertile and only four look like theres life .
What would cause blood rings?
Temps been at 37°C and i put a thermometer in at the start and it ran true.
Egg turner, turns every 2 hours
Humidity has been between 50 and 60, but it can be hard to keep it so does drop and spike, but didnt think that would be a problem? Air cells are good
Our chickens are getting older, would egg quality have an effect?

 

[JaeG]

Leave them in and candle at day 10. Sometimes a blood ring turns out to be a really big vein. If the 'blood ring' fades, then it does mean it has died. There's no danger leaving them in a few more days just to be sure. Older chickens could produce less hardy embryos so that's something to take into account.

From NZ!

 

[Welshies]

37 C is a bit low. It should be 37.5 C (99.5 F to 100 F), if it's a forced air.
If a still air, it should be 102 F.

 

[chipens]

37 C is a bit low. It should be 37.5 C (99.5 F to 100 F), if it's a forced air.
If a still air, it should be 102 F.

Just checked, it is set to 37.5. It has a fan in It so i sapose thats forward air?

 

[chipens]

Leave them in and candle at day 10. Sometimes a blood ring turns out to be a really big vein. If the 'blood ring' fades, then it does mean it has died. There's no danger leaving them in a few more days just to be sure. Older chickens could produce less hardy embryos so that's something to take into account.

From NZ!

Yes I have left them in just in case I'm wrong as a couple i wasn't sure, i usually leave them all in till lockdown. The last batch i did before christmas had a few blood rings too but not this many, think it could be because the chickens are getting older.
Hi from nz too

 

[Welshies]

Just checked, it is set to 37.5. It has a fan in It so i sapose thats forward air?

Yes.

 

[JaeG]

Yes I have left them in just in case I'm wrong as a couple i wasn't sure, i usually leave them all in till lockdown. The last batch i did before christmas had a few blood rings too but not this many, think it could be because the chickens are getting older.
Hi from nz too

It could also be our stinking hot summer! (That's me today in Auckland)! I've got quite a few chickens that have stopped laying because it's just too hot. The nutrition your birds are getting can affect the outcome of your hatch so if the hot weather is causing them to eat less that could be another factor.

 

[chipens]

It could also be our stinking hot summer! (That's me today in Auckland)! I've got quite a few chickens that have stopped laying because it's just too hot. The nutrition your birds are getting can affect the outcome of your hatch so if the hot weather is causing them to eat less that could be another factor.

Possibly our chickens arnt laying much either, my humidity is hard to keep atm too during winter it would be quite stable.