Black vomit in laying hens without the use of CU or animal meal in the food or what other ethiologies?

Of laying hens 80000 -mortalite 80 subject per day -Incontinuous empty of food, crop lacerated and filled with a greenish black liquid, empty proventricle, brownish irritated gesier with adherence of the cuticle, some hens have a greenish black roughness coming out of the mouth excessive production of ACID by the proventricle