Poor hatch rate: how do I know if it was humidity: to high or low?

[JodiLynn]

I had seven eggs go into the bator 3 days ago. 1 hatched fine and on time, almost 36 hours later anouther peeped and started to unzip. After I got home from work it still had not made it out so I assisted. It is chirping and drying off as we speak. All the other eggs were dead, 6 that were fully formed and one dud. A couple looked like they had not absorbed the yolk but were fully formed when I did an eggtopsy. I cut into the top and it was very wet with yellow yolk on top. A polish had no yoke but it was pretty wet with liquid surrounding it.

I used a havobator with no water (25-35%) humidity most of the time. I put the eggs into a little giant for lockdown with humidity set to 60-65%. I did have some temp fluctuations from 93-102 a couple of times. The humidity stayed pretty consistant.

How can I tell if my humidity is to high or to low? I assume the temperature fluctuation had a negative impact on them as well. I am having a hard time keeps the little giant temp stable so it may have to be used for emergency's only. If so is it possible to hatch out different hatch dates of 1 week apart in the same bator?

Thanks for any advice or thoughts on this!

 

[Big A Chickens]

I have found that going below 30% humidity does not work well for me. I usually ended up with a 40% to 50% hatch rate when going below 35% humidity. I now run all my hatches at 35% to 45% for the first 18 days depending on how the air cell develops and 65% to 70% for the last 3 days. My temp stays steady a 99.5 to 100 degrees and the lowest it has ever dropped is to 97 degrees when I'm candling. The fluctuation that you had could have played a part in it depending on how long the temps stayed at the low and high points.

Some other factors could be detached air sacs, shipped eggs ( in which I've never gotten above a 50% hatch rate with them).

I use 2 thermometer/ hydrometers in my bator so that I can have more accurate readings.

I think it will be kinda risky to try to run staggered hatches at 1 week apart in the same bator, since you will need to increase the humidity to a higher level for the batch that is due to hatch at the same time pushing the humidity way to high for the second batch which should be at a lower level.

What I did was, I built 2 bators from some plastic insulated igloo coolers that I had no use for less that 20 dollars each and bought a little giant egg turner for one. That way I can run one full time as an incubator and the 2nd as a hatcher. That way I don't have to worry about how I am going to adjust my temps and humidity to satisfy 2 or more different hatches.

I hope this helps.

 

[cochins1088]

But I would like to add a few things. Optimal humidity is different for everyone. It depends on the area you live in, the season and sometimes even the room of your house. Personally, I get the best hatch rates with 30% the first 18 days and 55-60% the last 3. To figure out what your humidity should be you either need to weigh them or candle them. For weighing, an egg should lose 12% of it's mass throughout incubation. I believe there are a couple of threads on here that can help you with the exact calculations. The other way is much more simple, but may also be a bit less accurate. There are pictures on google images showing what the air cells should look like on certain days (I'll attach one at this end of this post) If the air cells are too large, then increase the humidity. If the air cells are too small, decrease the humidity. There is one other thing you may notice. The picture is for a freshly laid egg. If your eggs were stored for a week before incuabtion, they may already have air sacs the size of day 7, thats ok. Also, as a rule of thumb less humidity is better than too much but neither are good.

Did you notice if your eggs had internally pipped, because it's possible the fully formed dead embryos with yolk drowned from too much humidity. But your levels sound good. There are a lot of factor as to why they don't hatch. And remember that optimal humidity is different for everyone.

And about hatching one week apart, yes you can do it but it should be avoided if at all possible. I have done it with sucess many times, but you have to really know what you are doing and be prepared. The raising of the humidty for a couple days shouldn't harm them if you are able to control the air sac development properly. The main thing people forget when doing staggard hatches is that chicks make messes when they hatch so you have to be prepared to clean the incubator out after the hatch in under 10 minutes. If you leave it messy, bacteria will reproduce like crazy.

Good Luck!