Probably not the best thing to use but it was what I had on hand. I have a broody hatching them, and I glued them on day 13 I was fumbling trying to get them back in the nest and they fell out of my hands. Just hairline cracks not dented in or anything, they are not bad at all and the eggs are still structurally sound, only one has a spider web look, that the hen cracked somehow. When should I peel the glue off though its day 18, the cracks are over the air cell on 2 of them. This is my first hatch so I dont know very much, I'm mostly just letting the hen do her thing, but probably worrying about her taking care of them more than I should.