Hello there: my duck eggs are due to hatch today . Two have pipped and are starting to zip but there are a couple that have these black spots that are growing. I am so worried. They have not pipped. Does anyone know what this means. The black spots are on the outside of the shell not inside. I have not opened or candled since lockdown. I have been looking all over this awesome site for similar issues. Please let me know if you know anything about this. Do they need help? Are they dead?I will post a picture. Thank you so much if you have any advice!