A couple of days early on shouldn't hurt. If you can get it down a little lower that would be good. Good luck with your eggs.
Edited by Katy - 9/8/08 at 8:16am
This is a good topic I have been trying to find answers to myself. My incubator has been running around 75 to 85 % with the center filled with water. I have a friend that has the GQF Sportsman and he runs his humidity at 80% the whole time. I have been told it is ok to have high humidity but not over 90%. So I really don't know what is correct.
During incubation eggs have to lose 12% of their weight by losing moisture to hatch. At a higher humidity this will not happen. The chicks will drown either while developing or the water will collect in the air cell and when they pip they will end up breathing in water. Incubating methods now are leaning toward very low humidity and most have been doing well with better hatches on around 40% humidity than the usual recommended 50-60% I saw when I first started researching hatching chickens. My last hatch I ran it 38-40% humidity and had a much higher hatch rate. I have never read or talked to anyone that suggested more than 60% humidity. Some don't even go over that amount during hatching. 90% is definitely too high and should kill most hatches. 60-70% are the numbers I most commonly see for the last few days during hatching. I've been keeping my hatching humidity at around 74% without losing any to humidity problems during hatching but I did get a couple sticky chicks last hatch.
To check the accuracy of a humidity gauge put it in an airtight bag or small container with wet salt. Not a liquid saltwater mix but just salt with enough water to keep it all wet for a day. After a day or 2 when the humidity reaches it's highest point it should read 75%. Correct for errors.
Just as an FYI I bought a humidity reader that also lists temperature at the local Wall-mart (May God Have Mercy on me for shopping there) and it is horrible. It READS but doesn't update very much and when I hit the "clear" button, it doesn't clear and I have to remove the battery for it to clear and start over again. *sigh* What to do oh what to do?
At least I know my humidity is down and to piggyback on what everyone else has said, I have heard that you want to keep the humidity to less than 50% also. There is also a good article in the Learning Center of BYC that has a guy named Bill Something-or-Other talking about DRY Incubation and how he got a great hatch rate out of it. Very intriguing.
Ok now the humidity is down to about 45%. Is this a good humidity to keep the eggs at? I'm on Day 5 and things seem to be going well...