Hello David, I'm Dr. Deb.
I recently came online and see that your question about Chloe hasn't been answered. I'm so sorry that you've had to wait for a response,but if you still need assistance, I'd like to help if I can.
This behavior of eating grass and dirt (and other non-nutritional substances) is called pica. The underlying cause of pica can be different for each dog who does it. The following are possible explanations with some more likely than others, especially if this is new behavior for Chloe.
1. Sometimes we see pica in dogs with anemia so it might be a good idea to have blood work done, if it hasn't been done recently.
2. Many times we see it with primary gastrointestinal disease; these dogs are probably experiencing a low level of nausea which could account for the pica. I've seen a fair number of dogs with Inflammatory Bowel Disease (IBD) eat dirt. Usually there's a history of intermittent vomiting and/or diarrhea. It's not a common condition to spontaneously develop in a dog this age, though.
Bloodwork is usually normal for IBD; it would take a biopsy to diagnose which most owners are understandably reluctant to do (especially in a dog this age).
3. Kidney issues can often cause secondary nausea and might explain pica but I would have expected increased thirst and urination and possibly weight loss if this were the problem. Blood work would need to be done to evaluate the kidneys.
4. If a dog this age starts to develop pica as well as other unusual behavior, then I always worry about a brain mass, unfortunately. These tend to be slow growing masses but I would have expected you to see other signs if pica has been present for a while.
5. Most of the time, we don't have a good explanation for the ingestion of dirt and grass; we have no clue why dogs like to eat it. ...but there are a lot of them who do:)
My dogs eat dirt and grass all the time but since I have some IBD issues with them, I always chalked it up to this problem. I'm not always convinced that this is the reason, though, since they sometimes just seem to eat it when they aren't having a flare-up.
It's not harmful in and of itself. If Chloe is ingesting dirt/grass where a number of other dogs have defecated, then I worry about ingestion of internal parasite eggs (such as round worms, hookworms, whipworms) or giardia oocysts. But the dirt itself doesn't seen to cause a problem in terms of irritation or obstruction. Sometimes the grass will cause some gastrointestinal distress (vomiting and/or diarrhea) if enough is ingested, though.
If you think that Chloe might be a little nauseous, you could try giving her Pepcid AC at a dose of 1/4th mg/lb twice a day. It won't harm her but I honestly don't know if it will stop the behavior.
It's not a bad idea to have blood work done in regularly in a dog this age so if this hasn't been done recently, I probably would...just to rule out any obvious problems.
I hope this helps; again, my apologies for the delayed reply. Deb