I don't know what incubator you're using. I started out with a Little Giant incubator many years ago. I initially had poor hatches primarily due to my humidity which was between 50 and 60%. I lowered it to around 40% and my hatches got better. Now I have the humidity around 35% during incubation and raise it to around 70/75% at lock-down and now the hatches have been very good. Awhile, prior to collecting eggs from my breeder coops, I put the birds on higher protein feed, 20%. In my opinion it helps to make healthier chicks if the parent stock is. I don't think regular 16% layer feed is adequate. I was buying some high protein feed from a certain manufacture but they discontinued it so now I give the parents Game Bird feed which is 20% protein. Currently my birds are molting so they are on the higher protein feed because their feathers are primarily made of protein. I do think the feed makes a difference, but everyone is different so each has their own opinion.