Chickens can't "vomit" or :"spit up". When they eat or drink, it goes into the CROP, which has no muscles. If there is drool or anything coming from the mouth, it is from an overfull (overflow) from the crop. A hard feeling crop is impacted. There are several methods of relieving (emptying) the crop. GENTLE massage may allow some contents to empty through the small opening into the small stomach. If not successful, surgical opening and removal of the contents is possible. Chicken Vet can do it (try to find one who treats chickens!!!!almost impossible in most areas). It can be done but cannot list the instructions here. SEARCH is necessary to locate the operation. It is usually a successful operation, but unfortunately, after healing, the situation is likely to recur. Keep her from any feed or water. Do not add to the problem by feeding or offering water or medications! Waiting is hard to do, but if you cannot treat it, the chicken may recover naturally, or will quietly die. Sorry. Long grass is one culprits of impacted crop. Goodluck.