A. It's not ideal as puppies and senior dogs have different nutrition requirements but if she manage to eat just a little bit it's not likely to harm her in any way.
A. Potentially yes, puppy food is high in calories which can cause obesity in older pets. Also it is high in fat and this can stress her pancreas causing pancreatitis. I would recommend you feed her senior pet food which is higher in fiber and lower in calories for her overall health and well being.
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