When I took Riley to PetSmart obedience I would just boil a chicken breast and cut it up into real tiny pieces.
I have also used Zukes mini naturals [I usually cut them into 2-pieces]
I just bought a bag of Fruitables.....
The Pumpkin/Blueberry....
They are a clover shaped cookies, so I break pieces off for him.
Amazon.com: fruitables: Pet Supplies
And I just bought a bag of Smartbites trail mix.
[
they have several different flavors.....also]
I found it at my local dog boutique for $4.99 a bag
Amazon.com: zukes
I also remember hearing, that dogs don't necessarly care about
the size of the treat....but Quantity.
[not sure how they know that.... ]
?!?! LOL
Hope This Helps!!