Hi, I have a four year old hen that has yellow/green watery poop, she is lethargic and will not come down for the roost, should I separate her from the rest of the flock? I've read some people give antibiotics where would I get this type of thing?, she has had some stress within the past couple of weeks with construction in our area and a new coop, I've also added two healthy new pullets to our flock.