Let me start by saying I am new to chickens. I picked up six chicks about a week ago at a chicken sale. Four are bigger and look to be a bit more mature. These ones look great. The other two are smaller, but have gained weight and the real scraggly looking one (the one with some patches of fluff missing) has grown in feathers, although it is still the sorriest one of the bunch. This little scraggly chick has started a loud chirp today. It wants to huddle under the largest chick and I noticed it had white diarrhea stuck on its bottom this afternoon. I swabbed this off with a Q-tip and dried it thoroughly. I started putting them outside a few hours a day two days ago and when I put the little one outside today while I cleaned the litter, it stopped its chirp after a while and pecked around. It appears to be eating. This afternoon was 90 outside, so everyone was warm enough. I reduced the temperature in their nest from 90 to 85 yesterday. Could this be the problem? Or have triggered an illness? The other chicks are flapping, flying and chest butting. The two smallest are not. Should I separate the two smallest out? I asked my local feed store for medicated feed, but they were sold out for the year. They gave me tetracycline and said to sprinkle some on the food. Is this ok to do? Or should I seek out another medication? Or is there a food supplement (I read somewhere, not sure where, to give yogurt and cod liver oil -- can chicks tolerate yogurt?) ? Sorry for my longwindedness - I am new to being a mother hen and I wanted to include anything that might be the cause of this little chicks chirp. Thank you for any advice on handling this little chick and preventing any spread of disease to my other chicks.