We have four pigs running together and one female is not eating this morning and being lethargic. She will get up when you approach her and she will nose the food but then goes back to their sleeping area and lays down. When the other pigs left the stall she went with them. They are in a free range area and do dig around but are fed twice daily with plenty of water access. The other three seem to be gaining weight fairly well and she has too but she is slightly smaller. Just worried and any suggestions as to what to look for would be helpful. 
