Small Air Sac in Incubating Eggs

johs · **Posted:** Wed Sep 28, 2011 10:55 am

Hi all,
Can someone tell me how low I can make humidity without harming developing chicks. I need to help the air sac enlarge before the 18th day so the chicks will be able to hatch successfully. They are at day 13 now. The air sack in most eggs looks too small for this many days. I'm pretty sure high humidity was the problem with my last hatch. There were several pipped and dead in shell. They pipped quite high on the big end. I've reduced it for this one but I don't think it has been enough. Obviously I will need to increase the humidity on the 18th day but I was hoping I can drop it really low for the next 5 days to help them out.
Any ideas?
thanks Jo

purefeather · **Joined:** Wed Sep 29, 2010 6:36 pm **Posts:** 736

G'day Johs, what type of incubator do you use? You probably already know this but I'll mention it just in case, it's not the volume of water that dictates the amount of humidity it's the surface area that gives more or less humidity.

andre · **Joined:** Tue Oct 13, 2009 5:21 pm **Posts:** 612

You can drop it down to 30% for a few days, then lift it to 50% for the last couple. Or if its a very small incubator it could be that the eggs hatching will generate enough extra humidity without needing to do anything.

johs · **Posted:** Wed Sep 28, 2011 6:39 pm

Thanks guys.

Incubator is a JN8-48 (Made in China). My initial test run was with a small number of eggs (many of them infertile). It ran a little hot and the humidity was too low. Second run it was pretty full. Still ran hot and humidity was still not right. This last lot I dropped the temp a little and played with the water but the humidity must still be too high.

Yeah I know it's surface area. :-D

I will have to empty the water channel and put some smaller containers in to get to 30%. One channel is about 50% and the two puts it up to 60-65%. Which doesn't sound that bad but the gauge must be off a little or something.

thanks again, Jo

andre · **Joined:** Tue Oct 13, 2009 5:21 pm **Posts:** 612

Go and get a digital hygrometer/thermometer from an electronics or hardware store. They are about $40 and the humidity reading they give is accurate enough. Use your other thermometer for temperature however as the one that came with the incubator will be more accurate.

purefeather · **Joined:** Wed Sep 29, 2010 6:36 pm **Posts:** 736

Johs, Andrewschooks has given you good advice. you could also check Bellsouth's website for more specific equipment.

johs · **Posted:** Thu Sep 29, 2011 3:38 pm

Managed to get humidity down to around 33% using two small Vegemite jar lids. :-D

I got a hygrometer/thermometer (actually a wireless weather station) on Fathers day 'cause the hygrometer started playing up. Being fathers day I got it for half price. :lol:

Must be considered a manly gift. It was the only thing I could find on a Sunday, from Dick Smiths. That was with the last batch of eggs.

The readings on the incubator and the weather station were different. The temperature was just a little different but the humility was heaps different. Not a constant difference either. Sometimes it was 5-10% diff. sometimes 20-25% diff, always lower too. I think I will have to invest in a wired one.

I'll check the air sacs again at 18 days (4 more days I think), when I take them off the turning tray and see how they are.

thanks again. Jo

johs · **Posted:** Wed Oct 05, 2011 12:15 am

Well they have started hatching. Still early. About 5 hours off 20 days. A little longer than last time.

Will have to turn the temperature down even more for the next lot. While the air sacs did increase in size only time will tell if it was enough for them all. Thanks again everyone. Fingers crossed.

Time for bed so we'll see how many there are in the morning.

johs · **Posted:** Wed Oct 05, 2011 5:53 pm

Well it's a bumper crop! 26 from 36 and still going. These are much smaller chicks so I think lowering the humidity for those 4 odd days has made a huge difference. They are, of course, all adorable. Can't keep any though.

Jo

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wickedwings · **Posted:** Wed Oct 05, 2011 6:11 pm

Just out of curiosity, how do you determine the size of the air sac? Is that just by candling? I don't have an incubator I just have to trust that the 2 silkies know what they're doing, despite the fact they're the dumbest looking muppets.

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