Just keep an eye on the appetite thing. One of my terriers suddenly developed a ravenous appetite and it turned out she had developed Cushings syndrome. She was quite elderly but it can effect dogs of any age. I did not pick up on it straight away as I just thought she was getting senile! Check with your vet a simple blood test will confirm and early treatment will lead to a good life expectancy. Probably nothing to worry about but always worth a check.