New member, New chicks, New questions

Hello Everyone!! I'm a new member (actually Bird Hearders Better Half), and as he posted, we have some new babies. Initially my daughter gave us 4 red sex-links , but hubby had to have more. It wasn't my idea, but he brought home 12 adorable lil fuzzybutts Friday night, and sheesh, who could resist?? Being he had to convienantly work on Saturday, I found myself building them a bigger nursery.( ok, he DID help cut the wood).
We had baby chicks about 5 years ago ( which I also didnt want LOL but ended up taking care of them due to me having more free time than him) But I still feel new to this. Luckily ( or maybe UNluckily) I have a job where I can spend most of the day reading the forum - and I DO- and now I have a gazillion ideas for our coop addition, and I have learned alot.
I have a concern, though. The chicks we got are supposed to be RIR's. We have a few that are very much lighter than the rest, with pure white wing feathers as opposed to multi shades of red/tan. Their legs are also more pink than yellow



They aren't my main concern though. It's the little peanut. Not a "packing peanut" but a baby that is just so tiny. The first few days we were really sure it wouldn't make it. It was just laying around looking very weak. A little extra attention and it is up on it's feet, but very very wobbly. It just stands there, rocking slightly on it's feet. When the others run by, the lil peanut almost falls over from being unbalanced. I havent seen her lying down. She falls asleep - hanging her head forward till it touches the ground. And she always seems to be standing alone. Yesterday, I noticed some poo stuck on her butt, so I brought her in, and rested her on a very wet warm soft towel till the poo loosened. Then I gently wiped it off. Today, she seems to be so much better. Shes still a very little bit wobbly, but much more stable. And she was running with the rest of the group a little bit. I saw her sneak under the other chicks to get to the food, but she took only a few bites. And shes still sooooo much smaller than the others. So, my question is-- the wobbling, and sleeping like this, is it normal in a possibly runt? Here she is snoozing after I wiped her butt:


I have probably alot more questions/comments/etc, but I think my post is long enough for now. Darn that Bird Hearder for getting me hooked!!!