oh, i dunno about feeding raw potato or starchy stuff even if it's liquid.....may get a little explosive :( keep puppies (and all dogs) lean, i would not try to get her to gain weight other than natural growth, sound like she's just fine the way she is. fat is the most calorie dense nutrient, but have to watch it, some dogs can get pancreatitis with too much fat. starchy stuff can help too, may be safer. some females can lose some appetite during their heat. don't worry about it, it won't stunt her growth or anything. dogs can go at least a couple days without food and not bat an eye.