I'm sure these have been answered before, but I can't find them in the boards. First, my hens are just now a year old. Lately I have seen the small blood spots. One egg a few weeks ago was so bloody inside that it grossed me out. What makes this happen and is there anything I can do about it? Second, how old is too old for hens? I cannot imagine getting rid of my girls, but I sell my eggs and don't want inferior quality. Third, getting new chicks this week. At what age can I mix them with my older girls? Thanks!