Hi
I have an 11 year old GSD. Other than his back legs seeming a little weak when he gets up he's a figure of health.
He's always been a fussy eater. In the early days I fed him a complete feed and took the "if he's hungry he will eat it" approach until I learned that he just wouldn't. So I switched to canned dog meat and a mixer which he liked. Although my gut feeling is that canned dog food isn't ideal. I normally feed him once a day in the evening.
He's now become quite fussy again and eratic in his eating. One day he will eat all of his food in the evening. Othe days he will eat it all if presented with the left overs in the morning, so 1 feed split over 2 meals. Others still he just won't eat it.
I've bought differnet biscuits and cans to see if he just fancies a change, but this doesn't seem to be it. His teeth/mouth looks fine. He will still accept a toast crust 
Any ideas? Is he just showing his age and needing "old persons" food like fish or chicken? I've heard that baby formula is a good high energy, easy on the stomach supplement.
(I hate the fact that the pooch I love so much is getting older. It does cause me to look for problems that might not be there because I know he can't go on for ever)
Any advice you can give would be gratefully received.
Thanks
x