is 40% percent humidity ok for still air?

[BaileyBoy]

i always thought it was fine but am now reading that its too high? is 40% ok for day 1-18 and then 60-65% for days 18-21+?

 

[Egghead_Jr]

It's a good number. I use 30-35% myself but it really depends on your home environment so no one number can fit all. Candle at day 7 and check the air cell growth. If it's a bit small then lower the humidity some or vice versa. Check again on day 10 and tweak it some more if needed. The diagram below is not exacting but a good guide for reference. Basically you don't want the cell too small or overly large but there is quite a range where chicks will hatch just right.

 

[DanEP]

I agree with egghead_jr as long as the air cell is growing your fine.

 

[dstinett]

Wow. My humidity stays at 50%