On average, the untreated HIV infected patient will progress to AIDS in about 5-10 years. Since 1996, the introduction of powerful anti-retroviral therapies has dramatically changed the natural progression of HIV infection to the development of AIDS.
You CAN feed your horse just hay, but you have to up the portions and it also depends upon the type of hay you are feeding. Alfalfa mix is normally the best but there again, you're goinng to have to feed more hay to make up for the not feeding grain when you are riding.
Entire textbooks are written on this topic, but the basics are: 1  Hay and other roughages provide nutrients and satiety for your horse.  On average, a horse must consume about two percent of dry matter of its bodyweight per day (A 1000 lb horse will need to consume 20 lbs of feed on a dry matter basis).