Shaking is normal of yorkies. Their 'fur' isnt fur..its hair, so its not as thick. This obviously means that they don't have the best coat when it comes to keeping warm. They also are smaller in size so they don't pack on too many pounds to keep them cozy either.
One medical cause for shaking is Hypoglycemia or low blood sugar, it is common in adult toy breeds, and Yorkies seem to be especially prone to it. Symptoms may include, but are not limited to, wobbly gait, muscle weakness, tremors or shaking, foaming at the mouth, head shaking, and loss of appetite. If your Yorkie experiences any of these symptoms give them Nutri-Cal immediately. Any delay could lead to loss of consciousness, coma, seizures or even death. If after administering Nutri-cal there is no improvement within 30 or 45 minutes call your vet! Nutri-Cal is available at most pet stores, and your vets office, you should always have it on hand. So, if she is not cold, or she has one or more of the other symptoms, assume she is Hypoglycemic.
