I have a 3 month old black coop marans. She started having milky white poop about two weeks ago, and her vent was out at that time. We tried many methods. Now her vent is OK, but still have milky white poop. Her appetite is good, and looks quite normal, except the milky poop. Can someone give me some advice? If some medication need to be used, can you also tell me where to buy them? Thank you.