Q: Why is my dog yawning so much?

Why is my dog yawning so much?

Within the last few weeks my dog has started yawning quite a bit. She is only a little over a year and a half old and is in good health according to our vet. She gets plenty of exercise but got very bored with her dog food lately. I just recently switched her to Blue Buffalo and Taste of the Wild the last couple of days hoping this will help her. I do believe she may have had a problem with her diet. Any ideas or suggestions would be greatly appreciated. Thank you.