I am new to chicken keeping. I bought eight 4 week old pullets. I have lost two. Gave worm treatment when one was sick. I now have six 14 week olds who have been happy and healthy acting. In the last week my Cochin, who is smaller than the others, is starting to stay to herself a lot. I don't see signs of mites, and I have not detected bullying. When I put yogurt out, she comes dashing out to eat with others. I have seen her feed with others, and she snuggles up with the rest on the roost at night. She likes laying in the nesting boxes, which none of the others have done. Many times when she is with the others she seems to be sleepy. She tries to snuggle with another chicken. What should I try to help her perk up? Do I need to separate her?