Ok, here is my theory. I've read a gazillion books on hatching eggs. Some swear by 35-40%, then to 60-65%. Others say 20 then to 55% (or close to that).
So, we all know that white and blue are base egg shell colors. They have no brown coating on them. Think of the coating as a paint layer. We all know what happens if you put really heavy coatings of paint on something....it is thicker. Well, an egg that is dark brown or dark green has a lot of coating on them. So, when hatching these dark eggs, you need less humidity. That makes the air in the incubator drier so that the moisture inside the egg can get through that thick coating to evaporate to the level it needs to. (It will be harder for the egg to lose moisture and create that air space when the egg has lots of coating on it)
So, on this last hatch, I noticed that the white and clear blue eggs hatched first.....then the darker eggs.....It is also harder for the chicks to pip out of the thicker coatings of brown or the darker colored eggs.
Anyway, I am thinking that if you are hatching dark colored eggs, you go with the less humidity. Light colored eggs, go with the 35-40 range. And like someone said, don't increase it too much at lockdown. So you wouldn't set the eggs at 20%, then lockdown at 70%. I would do either the low humidity (20-25%), then lockdown with the lower levels (50-55%) for dark eggs and the higher humidity (35-40%), then lockdown with the higher levels. (60-65%) for white, blue or light brown and light green eggs.
So, that's my theory for what it's worth.....
But, do whatever works for you!
So, we all know that white and blue are base egg shell colors. They have no brown coating on them. Think of the coating as a paint layer. We all know what happens if you put really heavy coatings of paint on something....it is thicker. Well, an egg that is dark brown or dark green has a lot of coating on them. So, when hatching these dark eggs, you need less humidity. That makes the air in the incubator drier so that the moisture inside the egg can get through that thick coating to evaporate to the level it needs to. (It will be harder for the egg to lose moisture and create that air space when the egg has lots of coating on it)
So, on this last hatch, I noticed that the white and clear blue eggs hatched first.....then the darker eggs.....It is also harder for the chicks to pip out of the thicker coatings of brown or the darker colored eggs.
Anyway, I am thinking that if you are hatching dark colored eggs, you go with the less humidity. Light colored eggs, go with the 35-40 range. And like someone said, don't increase it too much at lockdown. So you wouldn't set the eggs at 20%, then lockdown at 70%. I would do either the low humidity (20-25%), then lockdown with the lower levels (50-55%) for dark eggs and the higher humidity (35-40%), then lockdown with the higher levels. (60-65%) for white, blue or light brown and light green eggs.
So, that's my theory for what it's worth.....
But, do whatever works for you!
