I'm sorry, I am new to poultry talk, can u please tell me what FBCM & bym means?Just candled day 8. Pulled 5 (order 2 dz got 35)of my shipped FBCM. Obvious red ring of death but think 3 more are clear. Couple have wonky air cell. Pulled 9 out of the 31 mixed I got from friend. Then three of my bym are goin strong.