My dog is also 2 years and 2 months old. He is lanky skinny also. I like him that way. Its better for your dog. As long as his activity level is fine and he is healthy and happy why more weight on? I ignore those who say wow he is so skinny all the time. Most have breeds that are bulky and just aren't used to a younger setter. Lab owners really comment. When their dogs tend to be, in my opinion, very overweight. Lumbering along with no zest in their step. Forget seeing them run. I think as they age and they slow down they will fill out more. But for now, I like my dog lean.
I just had a look at him - he is a beautiful dog. I am sure, with these eyes, he knows how to get his way...
One of my dogs, Gina, is a skinny little thing, too. But then, she loves her runs and her play.
I am not an expert, but our vet once told me "her coat is shiny and her eyes are clear - she's perfectly fine".
I am not a fan of thin dogs and err on the side of having them well covered. I hate having them in show condition!
When I want to put condition on my dogs I add extra lamb to their diet. For comparison, one of my dogs gets fed 500 grams twice daily plus all his treats (biscuits, chews, pigs ears) and snacks (share of my breakfast, lunch, dinner)! His meals are made up of 1/2 cup dry food, 2 chicken necks, salmon or sardines and either lamb/veges/fruit or beef/veges/fruit. I buy the latter premixed and everything is fed raw. The dogs also get extras such as cheese, eggs and have 1/2 cup of milk on their meals.
My dogs also get a lot of free running exercise, at least 2 hours daily.
The starting point i always think for trying to build up a thin dog is to give them a good worm dose using a wormer which cover all worms.Then to give them 2 feeds per day like you are doing. At least then you will have eliminated one cause of an underweight dog.Hope this helps.?
Another consideration, is he gluten sensitive? In the UK some years ago, many thin Irish Setters were found to be and a study was done on it. The inside of the stomach is covered with little tentacles called villi and these are what absorb the nutrients from the food, if a dog is gluten sensitive the gluten causes the villi to shrink and die back, the consequence is not all the nutrients are being absorbed, when you remove the gluten from the diet, the villi will start to recover and eventually regenerate. Your vet can do tests, but why not just try putting him on a gluten free diet for a few months to see if it helps.
I didnt know that a sensitivity to gluten was common in setters!! But by trial and error I have put Milo on a gluten/wheat free dog food and the difference is amazing!!! Milo was always a fussy eater and never put on much weight(always around 27kg) and he is a big boned, tall setter! After a couple of months his bones now look nicely covered, his energy levels are better and his coat has thickened up and gone darker too!! He looks great! And his appetite is back! So maybe give that idea a go, as Rosie has said!! I must get Milo weighed to see how much he has gained!