Sick Chicken Don't Know What To Do?

I am new to chicken owning we have 5 hens. One of our Silkies (she is 5 months old) started acting a little weird yesterday. She just wasn't running around with the other Hens. Today I went to let the chickens free range and noticed that she had layed right under the larger chickens perch and got pooed on twice last night. Usually our bantams always stay together and sleep together. When I let all the chickens out she just layed in the same spot she must have slept in. I carefully pulled her out and got the poo off of her. Now she is inside with me and is not doing much. She is just laying with her head tucked in her furr/feathers. She doesn't want to eat or drink and she will look up to see whats going on when I pet her or move her but then sticks her head back in her feathers. Not sure what to do. That is the only symptom she seems to be breathing fine and nothing is coming out of her nose. She is sneezing every so often but not much.