I have a 16 months old neutered boy. He gets moderate exercise (45-60 minutes walk) a day, eats 1.5 cups of dry kibbles (taste of the wild) a day. He weights almost 28 lbs. When I did a search on this forum, everyone's corgi seemed to weigh over 30 lbs and eat much less than he does. So my question is does my boy have an internal parasite or something? He has been battling with mange for a long time. Ivermectin helped temporarily but as soon as he was off the med, the mange came back. Could it be become his immune system has issues?
??? Is he a Pembroke or a Cardigan? Cardigans are a little larger than Pembrokes, although some Pembrokes can be big enough that 25 pounds or so might not be overweight. Have you asked your vet about this? How much does the dog food's label say dogs in his supposed weight range should be served?
The standard advice is to feel for the dog's ribs through its fur. If you can feel the ribs without a lot of dramatic poking around, the dog is probably not overweight.
Ruby the Pembroke Corgi (about 20# at about 2 years) gets a cup of kibble a day plus a dash of the home-made dog food I make for Cassie the Elderly Pembroke Corgi (23# at about 9 years). Cassie gets about 3/4 of a pound of food made of chicken, turkey, or pork + Costco "Tuscan" vegetable mix + oatmeal or sweet potato or rice or squash. Both dogs maintain their weight without a great deal of exercise.