I got my first batch of chicks a few days ago. One seems to have poo built up, I tried gently washing but it doesn't want to come loose. Ive read of pasty butt but also umbilical cords that you shouldnt pull on. Having a hard time telling what's poo and what's possibly something different. The fresh poo wipes of but that chunk won't budge. Can't tell butt from belly button lol. Any suggestions appreciated