Chicken egg incubation success rate

[LisabethBrooke]

I have attempted to incubate chicken eggs twice now. Its a still air incubator. The first time I attempted I hatched 17 out of 40. The other eggs had either stopped developing at various points or weren't fertile in the first place. My second attempt to incubate eggs is down to its last 2 days and I have had to dispose of about half of the eggs that I started with in the first place. Am I doing something wrong or is this normal?
First time -
Temp was at 99 (the incubator thermometer says "good temp")
Humidity for the first couple weeks was 55%-60% - per instruction manual
I turned regularly, but didn't candle

Second Time
Temp was at 100 - I read some reviews that said the still air incubators needed the higher temps
Humidity for the first couple weeks was about 45% and then 55-60% until present. I just dumped more water in because as I understand it there needs to be higher humidity towards the end. If things go the same as before I expect the humidity to shoot up to 75-85% once they start hatching.
I turned regularly and only recently candled.

Any advice is highly appreciated. I hate throwing away partially developed eggs.

 

[Butterflygirl50]

I have attempted to incubate chicken eggs twice now. Its a still air incubator. The first time I attempted I hatched 17 out of 40. The other eggs had either stopped developing at various points or weren't fertile in the first place. My second attempt to incubate eggs is down to its last 2 days and I have had to dispose of about half of the eggs that I started with in the first place. Am I doing something wrong or is this normal?
First time -
Temp was at 99 (the incubator thermometer says "good temp")
Humidity for the first couple weeks was 55%-60% - per instruction manual
I turned regularly, but didn't candle

Second Time
Temp was at 100 - I read some reviews that said the still air incubators needed the higher temps
Humidity for the first couple weeks was about 45% and then 55-60% until present. I just dumped more water in because as I understand it there needs to be higher humidity towards the end. If things go the same as before I expect the humidity to shoot up to 75-85% once they start hatching.
I turned regularly and only recently candled.

Any advice is highly appreciated. I hate throwing away partially developed eggs.

 

[Butterflygirl50]

If your eggs were shipped to you, the average hatch rate is 50% although some luck out and get better results.

I'm setting up for my first incubation of shipped eggs from three different states. I ordered double what I needed going by the 50% hatch rate. If they all hatch I'm in trouble lol.

Hope you get the answers you're looking for.

 

[LisabethBrooke]

They're from my own chickens actually. I assume every egg is fertilized because I have 4 roosters and 11 hens. But the roosters fight over who gets the hens, haha.

 

[Chickassan]

I had better luck with shipped eggs this go than my own, very small hatch three out of four shipped hatched but on one out of two from my girls. Your setup is almost identical to mine except I had an auto turner.So this time you are set it is just up to the eggs. If it doesn't pan out the only thing might be that your incubator thermometer and humidity gauge isn't reading correctly to begin with, so you would have to get another to go by.Good luck.

 

[The Moonshiner]

What brand incubator are you using? Some brands have never worked well for me. For a small incubator i only use hovabators now.
Also your first post you mentioned some werent fertile but your last post you mentioned they should be.
If they arent fertile then that would be a whole different issue. It makes a huge difference in hatch rate if youre counting nonfertile eggs or if youre not counting them.
Personally i go with a lower humidity during first couple weeks. About 35% to 40%. Seems different humidity % works differently depending where people live.

 

[LisabethBrooke]

I assume all my eggs are fertile because of the four roosters to eleven hens thing. But when I candle them after they should be developed and they're still a clear egg with no visible development what so ever after 16 to 18 days I assume that it wasn't a fertile egg to begin with. As far as I know there isn't a way to tell if it's a fertile egg or not before incubation. Please tell me if there is and I will definitely eat the unfertilized ones.

I think the type of incubator I have was a little giant incubator. Its a Styrofoam box with a clear lid and a still air heater with a display screen.

 

[LisabethBrooke]

So it is now 2 days past the day 21 mark of my second incubation, and I have only hatched 4 chicks. 3 of the Eggs pipped and started zipping and then died, I have no idea why - that's disappointing (and depressing). And the rest haven't done anything.

I assume its because for some reason the humidity level dropped from 70% when the chicks were supposed to be hatching down to about 40%. That is the only reason I can come up with. Otherwise everything seemed normal, just no hatching eggs.

Any ideas what I did wrong and how I fix it for my next incubation?

 

[Wickedchicken6]

Did you check the thermometer and hygrometer of the incubator with a trusted, calibrated thermometer and hygrometer? A hatch that is too hot or cold can suffer and fail to hatch properly.

Temperatures for a still hatch should be higher than 100. I believe it's 101 or 102.

The humidity could have a bit to do with the hatch if eggs lost too much...or not enough and the air cells weren't the correct size.

It's possible the lack of a proper diet can affect hatching rates. There can be numerous reasons.

Editing to add: This is a good thread to visit to ask questions. I have air in mine so I'm not as knowledgeable regarding still air incubating. I'm sure someone can give you a better idea regarding still incubating temps.

https://www.backyardchickens.com/threads/hands-on-hatching-and-help.1081034/

 

[LisabethBrooke]

I free range my chickens. So they're out eating bugs and what ever they find all day. We have a hay field just on the other side of our yard that they love - its full of hay that they dig in, and seeds and I'm sure a helping of mice to catch and eat. Then at night I put them back into their caged yard and coop with layer feed. Do I need to supplement their diets any?

I will definitely look into the thread thank you!