I would definitely consider switching... especially if it is stressing you out that she's not eating...
Here are the many reasons why myself and the breeder + other owners from recent litters, have switched.
My reasoning:
First he wasn't eating well enough, he had constant eye goup, and was eating his poop every day! When I got him completely switched to a grain & wheat free food he stoped eating his poop, he loves his food, even though the kibbles are bigger, they eye goup only happens every once in a while, usually when we travel. The food definitely helped in that case. I also suppliment with Trippet, it gives that little extra kick to make the food tastey. For that size she should eat around 1/4 cup of this food daily and 1/8 of the smallest size can of tripe twice a day (if you can't get tripe talk to the local pet food store they may be able to find something similar). That's what Harley eats, but he's a little smaller. I wouldn't feed more tripe than that, just more kibble if needed.
My breeder decided it was time to switch, My dogs mother went through a terrible time having the puppies (she also retired the dog even though it was her first and only litter... she's big on letting the dogs live a proper life and NOT over breeding) The mother could not hold weight, lost ALOT of her hair, and was having troubles growing it back (I've heard that sometimes they do lose hair, but the lack of regrowth was the problem). Eye goup was a constant on all of her dogs, and thier coats were bland, not a lot of shine. There was an instant change once the switch was complete. She switched to Natural Balance, I couldn't get it close to my house so I switched to NOW! the ingredients in both are similar and have equal nutritional value.
Other dogs in the litter, and other litters: They had similar problems. The eye goup was a uniform problem with all of us. one could NOT get the dog to stop eating poop, and a few had allergic reations. All problems improved significantly if not completely once a food switch was done.
I am extremely disapointed with Royal Canin, Very happy with NOW! NOW! does have a Yorkshire Terrier food, I will only be feeding the general because the store only carries the general, I've talked to her and decided that I'm ok with the general, because I suppliment with the tripe.
I hope this helps... just remember if choice is limited, go with something that is Grain Free and wheat free, if you can find something that says allergen free, that's a bonus. You want absolutely NO bi-products. The first three ingredients are the largest component of your food, the first ingredient should be some sort of meat, NOT CORN. corn is a filler, essentially you have to feed the dog more to get equal amounts of nutrients. which leads me to the next point...
you may think that this might be an expensive switch. I priced it out. I paid way more for the Royal Canin, than I did for the NOW!
Good luck! There are plenty of articles on choosing foods for your dog. I but most of them summarize the above. I also caution you if you ask your vet about food. it has been my experience with both dogs and horses, that vets wont make the decision for you, A lot of them make money by carrying brands like royal canin, etc. I've watched videos where a vet is promoting a kibble that the first ingredient is Bi-products... so be careful. You are better off to ask a trusted dog friend who has loads of experience, or listen to the opinions of people on this forum. That's how I learned, I just kept asking, and taking in all the information people gave. Another great site to join is Zoo-too I think it's called, I found that forum befor Yorkie Talk, and between the two of them I learned ALOT!
Best of luck.
