I have noticed my 6 year old grade Quarter horse has a large belly but has ribs. He also has really thin withers with hollows behind him and you can see/feel the top of his ribcage. He has a little bit of an upside down neck as well. He is well fed, has dapples all over, and looks fat but there are ribs showing and his belly is big. He is routinely dewormed. He is on free choice to hay,water,and salt and on 6 lbs daily of Nutrena Triumph 10/10 (just switched to it) and since I got him, he has been on Nutrena Compete, Purina Omelene 500, and Purina Omelene 200. He has also been on CoMega supreme and Red Cell. The first pictures are more recent. *Note* The previous owner said he has always been thin on top and I have also recently attended a Cargill/Nutrena nutrition seminar and they recommended their Triumph 10/10 for him because they thought he was lacking amino acids because of the lack of muscle.