Hi Wendy and welcome to the Forums! Origen is a great food but very rich, and lots of Shelties don't do well on it for that reason. It's just too much for their digestive system. There are many good foods on the market, depending on what you're looking for. I'd keep a 14 week old puppy on puppy food at least until 6 months. Fromm, Merrick, Nutro, Wellness and others make good ones. Check the ingredients before you buy, and look at the nutritional values. Very high protein foods aren't always good. A range of 25 to 35 percent is best.
Stay away from any food with by-products! This is different from meat "meal" which is fine. Corn, wheat and soy are other ingredients you don't need. The Whole Dog Journal has an excellent comprehensive list of dog foods and ranks them. You can find it online. Hope this helps!