IfI had a pound for every owner who had told me their dog would only eat such-and-such, I would be rich!  Dogs are not naturally fussy eaters - but can easily learn to be if their owner encourages them.  The classic scenario is when the new puppy or dog refuses to eat the dog food placed in front of him.  Worried, the owner promptly offers him something better - perhaps, chicken or eggs or fish.  Yum yum, says the dog - this is much better and so the next time he again refuses the dog food and guess what, his owner produces the tastier nosh.  Bingo!  We now have a dog who "only" eats the very best cuisine...

Just for the record, in readiness for their new homes my young flat coat's litter were all introduced to all kinds of foods: rice, cereal, egg, tinned food, dried food, fish, veg etc.  As soon as eight week old Rosco came home I tried him on what I knew he had been happy to eat before.  He turned up his nose and scampered off to play.  After a couple of weeks of eating virtually nothing I asked my vet to check him over.  He was declared 100% fit if a little skinny and so I ignored his pickiness: I left the food for a short while and if he chose not to eat it was removed and nothing else offered.  Three years on, Rosco is little different - he simply finds food and the act of eating too boring.  He eats reasonably some days, other days he leaves it all.  But he is never, ever offered anything better!