Dry incubation? Not adding water to the incubator?

Hey everyone,
Back when I learned how to do this, I was taught you needed to add water to the incubator in those little grooves in the bottom of the incubator. I read something this spring about not adding water, so figured I'd try it. Does anyone do dry incubation? Humidity here where I'm at isn't normally high, but it's at 38% currently. I don't have a hydrometer in the bator.
Also, is day 4 too soon to candle? They're leghorn eggs.

You will see things on white eggs early but I don't bother candling until near day 10 to toss out the quitters. At that date it's obvious what are continuing and what never started or quit early. Clean your hands prior to candling if you plan to do it a lot through incubation.

Dry incubation is a bit of a misnomer. Drier incubation is more accurate. Not many forgo water all together and they are in wetter climates, like wet spring after winter heating is over. Using a hygrometer in incubator (calibrated with salt test first) most of us run 30-35% RH for first 18 days. In reality you can candle to watch the air sac growth to monitor your humidity that way. It doesn't matter if you run dry for X many days then candle to find the air sac is growing too fast so add water to retard it's growth. The real deal is an average humidity that results in the right amount of moisture loss in egg is the right one. You'll find 30% RH right through is darn close to perfect for air cell growth. I manage that in my climate by using small water glass or two sitting in the incubator. The troughs are far too much surface area to use during incubation unless heating with wood or desert climate.

I run 45% first 18 days.. 70 last 3..
I use a small pill bottle next to egg turner by motor..
That's usally all I use first 18 days..
Ya need a guage to monitor it.. I'd get one.. not to late since your only at day 4..
I'd wait to candle..
38% humidity in the room..doest mean it's 38 in incubator it's dryer in there due to the extra heat drying it out