My chicken is acting very droopy. She's not with the flock anymore. She goes into the egg - laying box just to sleep. We separated her from the other chickens today. We think it might be sour crop. I have read through all the other posts about sour crop, but she seems to have a different situation. Most of the fluid is out but there is a big lump of gravel and pebbles in her crop. Her crop is practically empty. Is this still sour crop? We feed her yogurt and her regular food soaked in yogurt. What else should we be feeding her? Please help.