Hi. I have one week of experience with chickens - so very new. I have 19 Buff Orpingtons I got from a breeder at one day old. 18 are twice as big after one week and doing well. One, which had pasty butt, is not growing at all. She eats and drinks and I keep her vent cleaned and lubricated with olive oil. I got her to eat a little yogurt, but not much. She may be more lethargic today, but has been fairly active. Is there anything else I can do?