I have a California White that started laying about 3 weeks ago. She's quite regular with almost 1 per day. Today she laid an egg that had blood on it, which has never happened before. I checked her vent and it looks healthy and their isn't any blood on her feathers. I know who it was that laid it because she's the only white egg laying girl I have. She's behaving totally normal as well. What causes it? I did a search on here but there weren't any answers, just 'I'm not sure, but it happens'. Is it the cold temps? The temps were in the teens when she laid it, but I had an EE lay one as about the same time today and that wasn't bloody. There's people that are much farther North than me that have chickens so I'm guessing it has nothing to do with the temps. I'm just putting it out there as a possibility. Here's some pics. The bloodiest portion seems to be on the leading end of the egg.