you are looking at blood rigs of early death - normally associated with bacterial or poor quality eggs.My Magpies & Saxony eggs have been in the incubator for 8 days now. Half of the Saxonys are showing development (so exciting!) but only 1 Magpie seems to be developing a few look wierd. I'm posting pics of the weirdos and hoping you hatch masters can tell me if they are just cooking in there or developing :-D
You should contact the supplier - explain that the other breed is doing well but this one did not - they may give you more eggs free
. We have those type As welI. The are more commonly called hog nosed snakes. I rescued a big one from my dogs last year. They do an insane death act when they are in danger, rolling and pitching a fit while pooping everywhere. Then they play dead. Then they just pull themselves together and leave when the coast is clear. It's a characteristic of that type of snake. Anyway, glad you told your gardener not to kill them next time...I find them in my garden too. Good for rodent control. I am sure they would be dangerous to chicks, but doubt a full size chicken would have any worries. 
