Hello I just want to Welcome you to YT
I personally do not feed SD
I don't feed any food that has By products in it.
Dogs need Meat not Meat byproducts.
www.dogfoodanalysis.com
If you post this in health and Diet you may get more answers...
here is that Link
http://www.yorkietalk.com/forums/forumdisplay.php?f=5
also here is a Link to get free samples.
http://www.yorkietalk.com/forums/showthread.php?t=76518