Blood in egg

[forbero]

Based on previous posts, it seems normal to have some blood inside the egg sac (not the yolk). I am trying to figure out if the blood I found is due to fertilization or just a blood spot. I do not think I have any roosters, but in addition to liquid blood in the sac, there was also a thicker chunk of blood (looking a bit like the fertilized chicken here: http://blogs.discovermagazine.com/discoblog/files/2008/05/chick.jpg, but not in the yolk itself- and no vessels like this anywhere). So 1) is it possible the egg was fertilized? and 2) is it normal to have blood, and some being thick, in the sac?

A bit more info- this was a brown egg laid by a chicken that has been laying for about 4 weeks. It was a double yolked egg.
Thanks!

 

[Peeper7]

What you are noticing are "blood spots" or "meat spots" which happen when the egg is being formed. It does not indicate fertility. You may notice this more when hens first start to lay. In some, it is hereditary and the hen would be culled if it were a commercial layer.
fertilization appears on the outside of the yolk as a "bulls-eye" white spot. There is normally a little white spot on the surface of the yolk but it is small and irregular. If the egg gets fertilized it looks very round with a ring around it.
Development cannot begin until the egg reaches at least 70 degrees so you would not see blood vessels.