She won’t gain any weight while having diarrhea, just feed one brand formula for now, feed the wet tin food that was the chuckest & wasnt al mashed up & sloppy or best to feed home cook boiled chicken & boiled potato while taking antibiotics & having her diarrhea… you need to firm up poo’s, check her gums make sure they are pink & not white, her gums need some colour in them, you don’t want her to dehydrate especially if it’s hot, also pinch & pull up her skin on 1 of her front paws after you have pulled up her fur/skin, does it go back to the bone quickly?…
