This is a little bit off the subject, but my neighbor has a little 5-pound Yorkie that is 7 years old. He has been happy and healthy all his life -- but he certainly is a skinny little guy. She says that he eats well, has been healthy, and has been skinny all his life. She has tried to fatten him up since she got him - but to no avail. And - of course, her vet has told her to keep working on it - but not to worry because he really is perfectly healthy, happy, playful, and affectionate - and after seven years of this, it's obvious he has no health problems at all.
One the other hand - my Yorkie is the opposite - he's a much heavier little guy - not fat - but does carry a lot more weight then her dog does.
So - hopefully - your little guy is just "thin" -- and still very healthy. It is good that he has a good appetite.
Good luck Carol Jean |