Have you tried adding tripe to his food? Most finicky dogs love this stuff! (That way you could get him to finish of the Wee Bit)
http://www.petco.com/product/15035/S...eef-Tripe.aspx
It also has good benefits:
http://www.thedogbowl.com/PPF/catego...84/dogbowl.asp
I noticed that my dogs gobble away more when I add a new ingredient or flavor rather. So I stocked up on canned food in several different flavors & rotate 2 cans until they are gone.
I have 2 picky eaters, to ensure that they CANNOT they cannot pick and choose what they like - I pulverize the kibble with the chopper attachment on my hand blender. This works ideally if you add it with canned food or an liquid supplement -- you could even add water. I started doing it for my 2 Havs that aren't picky eaters because when I started supplementing them with Salmon Oil it seemed more of it to end up in their beard! Ahh, what a great lingering fishy smell!
Might also try using one of Honest Kitchen's all life stages dehydrated formulas as a topper 1 TBS or substituting half his food with it:
http://www.thehonestkitchen.com/index.shtml
* Love this stuff! Yes, there is a bit of sticker shock when you look at the cost up front. I incorporate into my adult dogs more as a food topper/gravy something to spice up their food. (Actually cheaper than buying IAMS dog gravies in the long run - not too mention healthier). They love it! A little goes a long way. I only add a Tablespoon to the adults dogs daily meal. They suggest rehydrating with 1 cup with 1 to 1.5 cups of water. To increase our dogs water intake I use 2 cups of water to 1 cups food. Makes it last even longer! It lasts us 10 days and thats feeding 4 dogs. So, imagine how much further it'll last if you only have one or two small dogs

We have yet to make a dent in the 10lb bag! Also, you might want to make a small batch as unused portion should be used within 48 hours. Or, freeze the other portion..*
I like Wellness Super5Mix Just for Puppy - all of our puppies love this stuff!