Im always the worst to judge candeling... the ducklings i hatched out i thought half were blood ringed but they were just rrally clear and see through so they looked odd. I always just leave them in there for a long time just to ,make 100%sure nothing is growing.Most look as if they are not fertile at all while others are either to dark to tell, or I just don't really know what is going on as its different than I have ever seen.
I have never seen a twim yolk while candling or incubating. I am not sure what you have thereAlso, I noticed two eggs that appear to be infertile but the yolk is very strange. It almost looks like their is an air bubble in the middle of the yolk that makes it so when it runs there are two separate sides of running yolk, but they still meet on the edges. I don't think that its twin yolks though... Any opinions?
