Since she colicked is she sanded ? I would start her on a double of psyllium for three days , and then regular dose for 7 days, take a glove and fresh poo that from the pile top so it has not hit the dirt, add water, and look and feel for sand.
I add the psyllium to bran, that has been wet, but not a mash . Is she drinking enough water ? Maybe she needs an electrolye .You can get some in a tube, or buy the powder to add to feed and water.
The worse case , could be liver failure. We have had some horses that had liver failure, started out with weight loss, colic symptoms, treated for worms had teeth floated, cbc's run, tubed and oiled for colic, added supplements,added hay, still had weight loss, then problems urinating and a fever.. Final dx after labs specific for liver and kidney, was failure. unfortunately no cure. Not contagious had that lab test also.