My yorkie is 7 months and weight 2lbs 8oz and yes she's a picky eater. You know what she did she ate her sis poo and it gave her a stinky smell to her. So check to see if there's any poo missing.
I decided to try raw meat and that solve everything, she gets nice and full so she doesn't have the need to eat other delicacies.
Everytime I take out the container of Primal she goes bonkers and she looks like she's been starving when she digs in her bowl. Here's the link to Primal:
Primal Pet Foods: Store Locator
Good Luck!!