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!