Hello, I'm new to owning chickens, and just got my first group of 3 1/2 month old buff orpingtons. The smallest one has been acting lethargic over the last few days. She is eating and drinking, but overall just doesn't appear well. The other two hens appear normal, and they are not picking on her at all. While the other two are happily scratching around the yard, she is just standing near the other two until they move to another location. Her vent appears clean, and her comb maybe a little pale (or perhaps I'm just being a worried mom). She is defecating, and they seem to be a little soft, but nothing overly concerning. Right now I have her resting inside the house with a heat lamp, what else can/should I be doing for her? Thanks!