Boxer wiegh to THIN!

Question
Hello, thanks for taking my question. I have a boxer that is almost 2 years old. At the last checkup, she only weighed 46 lbs. The vet says that she has nothing wrong with her and that she will always be skinny. I saw your answer to dans questions. His photo of his boxer looks very much like mine. Her rib cage is showing. I feel horrible because everyone asks if i feed her?! and of course i do! she eats all day long! I am a golf course superintendent. Since my girl was a pup she has been on the course with me every day! She loves to run around up and down the hills and across the fwys for 4-5hrs a day! I don't know if this is setting off her weight gain but ever sense she was spayed at 6 months old, she has gained only 10lbs. I just want her to fill out like every other boxer i have seen. Right now she is pure muscle that is very defined. My other question is about her sleep. She does sleep a lot! but I'm assuming thats because she runs forever and ever! Does this play a roll in weight gain? How can i get her to gain weight?

She eats Purina Dog Chow for large Breeds in the green bag.

Answer
Change dog foods; she needs a high protein natural dog food that does not contain corn and corn gluten. Diamond Lamb and Rice and Chicken and
Rice is good. Blue is good. Any brand that mimicks those ingredients.

46 lbs. is a little small, but not unusual. I prefer a female to weight 50lbs. minimum.

Add 1 cup whole, plain yogurt to her food three times a day for a month. Then reduce to once a day to increase her weight and aid in digestion.

You can cook ground turkey or ground chicken and add rice and carrots also, and mix it with her food.

Feed her 4 times a day because she exercises so much- she needs more protein and energy that the average dog.