Orijen is a GREAT food and in my opinion, a million times better than RC. I think RC costs way too much for the low quality.
A lot of Yorkies have have had problems with allergies and itching due to the corn content.
For future reference, posting threads like this in the Health and Diet section will get you a lot more responses! Here is a link to it:
Yorkie Health & Diet - YorkieTalk.com Forums - Yorkshire Terrier Community
Good luck!