My 4.5 lb yorkie eats half the caesars square can and would eat it all if I let her..lol she loves that food.. Good luck and look in her mouth and see if you see any bad teeth. Yorkies are prone to it especially using the wet food. If she's backed up you can use a baby glycerin suppository half of one of those up her fanny...
give it some time and bingo she will go.