Check her crop first thing in the morning just to make sure it's empty.
Can you get a fecal float to see if worms and/or Coccidiosis are a problem?
I'd get some probiotics into her. A little buttermilk with white cooked rice would be good or you can give a little plain quality yogurt.
Any of your feed get moldy or are they eating any spilled feed that has gotten damp/moldy?
I'd check her crop first thing to make sure it's emptying.
If possible, get a fecal float to see if worms are part of the issue.
See that they are all drinking well and eating. Do check your feed for...