Well, a few possible explanations.
#1 If she is super active, she may simply not be eating enough calories to maintain her body weight.
Imagine the swimmer Phelps. If he didn't eat over 10,000 (or some ridiculous number of calories a day) he would be even thinner.
#2 Intestinal parasites
I can't entire trust the dewormer that was given over the counter, however, I am more concerned about the other super common microscopic bugs like giardia and coccidia. These can even be present with no diarrhea.
Bring in a fresh poop sample to the veterinarian. Ideally, within a few hours. Request that it be sent “OUT” to the laboratory instead of being looked at in the hospital (more accurate that way). We are not interested in only worm eggs, but also checking for the very common microscopic bugs like giardia and coccidia. These types of parasites will not be cured with over-the-counter dewormers.
If you are feeding a regular dog food, I have no reason to believe the food itself is deficient or not caloric enough.
Heartworm disease is not a likely explanation for this symptom. If there was coughing, respiratory problems, exercise intolerance, than I would change my mind.
Certainly, if not on heartworm preventative a basic blood test including a very simple heartworm test would be wise anyway.
Lastly. She may be skinny, but you need to have your vet see her, and tell you her BCS-body condition score.
So many dogs are overweight that the typical ideal weight seems thin. For example, you shouldn't be able to see ribs but easily feel them. Also, there should be a bit of a waist, kind of like a women with an hour glass figure.
So, find out her BCS from your vet.
If there is anything I have not covered for you, please use the REPLY button, and I will happily continue to chat. I hope you have found my advice helpful or informative. Please remember to click the "ACCEPT" button (EVEN IF YOU ARE A SUBSCRIBING MEMBER). Just Answer will only credit me for the time assisting you when you click accept. .Leaving feedback and a bonus is not required, but is greatly appreciated!
Please excuse any delays in my responses, as I regularly attend to hospitalized patients and daily examinations. REMEMBER: Even after you click "ACCEPT" and your question closes, you can still review our discussion and follow-up, if needed.
If you would like to ask any NEW questions in the future, you may request me through my profile @
Molly is skinny, her ribs are clearly visible, and her hip bones are protruding as well. Since the other two dogs are not skinny, should I check them too for parasites? Wouldn't all of them have it?
Not necessarily, but Yes, I would have separate poops submitted just to be safe.
Also, if they always finish their food, I would start working with your vet about the type and volume of food being given, as they will likely want to change the amount and/or brand of food.
One more thing, is the test for heartworm and parasites expensive?
No. Many hospitals offer a mini blood profile that includes a heartworm test for under $100. That way....
hold a sec...doorbell range. be right back
Or, you can get just the heartworm test for probably anywhere from $25-45.
Oh, the fecal test.
You will pay more for that. I strongly recommend you make sure you have a vet that sends that sample out to a laboratory and that the test includes a "giardia elisa"
This combo test will likely cost about $35-45 as well.
The poop test is A LOT more accurate when sent out to a lab. Otherwise, you are at the mercy of a likely unlicensed veterinary technician reading the sample.