I bought this stuff called Hatchright. You spray it on before you set the eggs then spray the eggs once a week till they hatch. I didn't get mine in time to spray them the first initial time but I've kept up with the regamin since. I candled yeterday and I just took out 3 clears. Most of whats in the bator are shipped eggs. This spray is suppose to provide nutrients to the growing chick thru the small pores in the shell. I'll find out how well it works,
 
I sprayed it on the test eggs and in 5 days I saw veins. I haven't candled the paints eggs yet. I'll let everybody know if this stuff works like it's suppose to. It's suppose to make more chicks hatch and they are suppose to be very healthy and be able to zip and pop right out of the egg. It's suppose to make shipped eggs more viable and get higher hatch rates. I figure it can't hurt. My last hatch rate was 11%. 1/2 the eggs where splash and the roo wasn't doing his job then died soon after so none of them were fertile to begin with, What didn't hatch died during lock down.