I'm new to this chicken farmin' thing. My 14 hens are dutifully providing me with a minimum of a dozen eggs a day. My girlfriend and I are in this together, and she's been selling them at work. One of her customers complained she'd had an egg with a blood spot that looked to be about a teaspoon in size. While I personally doubt that, I'm curious as to the danger, if any, of blood spots. We offered a dozen eggs as replacement, but she turned down the offer............but she has never bought any more from us. All the reading I've been doing on blood spots indicates several causes. The only one I think I might be guilty of is too much light. It's been dipping below freezing here in Central Oklahoma pretty much every day or so since before Christmas and I've installed a Red Heat Lamp in their coop attached to a Thermo-cube. So there is light in the coop almost 24 hours a day. I'm going to get a popcorn tin and install the lamp inside that with ventilation holes to solve the problem. I'm not concerned about vitamin deficiencies because I've covered that area pretty thoroughly. Their feed stays dry, so there's never any mold in it. I don't have gun shots or loud noises being made which might cause it. But does anyone have any thoughts on the matter which might help a chicken newbie?