And, to add to Mike's great post just because a bird weighs 850 grams one day and weighs 900 grams the next does NOT mean the bird gained 50 grams of muscle mass. It probably still has food in its system so your weight isn't really accurate. I don't know how many times I've heard people say their bird gained or lost huge amounts without understanding that. That's why it takes several days of increasing the weight before the bird finally ACTS fat and sassy. And several days of lowering the weight before it acts sharp. Unless you're not feeding it and you KNOW the only weight being lost is actual weight and not food in the system being passed through. This is where watching your bird's mutes comes in handy. Big, huge slices means the bird has plenty of food in its system. Small, green centered mutes mean the bird is empty and any weight loss is real.