Could anxiety cause a dog's poop to turn green?

Ok first problem is her diet. I realize you're just sitting, but her owners need to feed her a higher quality food. Meijer brand dog food is most definitely crap. Even a step up to Science Diet would be better than that junk. Her stomach is probably not handling the junk well. She might also have a bug causing the poop issue. My dog had green diarrhea at one time and the doc said it was probably a bacterial thing. He gave us meds for it. Call the owners and let them know. And for God's sake.. tell them to reconsider their food choice.