Here is another great video from Dennis of hawkbait lofts, he shows how he adds garlic to his birds drinking water once per week. He simply takes 4 cloves of ordinary garlic and removes the skin then pokes holes in them ad adds them to one gallon of drinking water. The garlic helps to purify the pigeons blood if you notice your pigeons nose is getting grey the garlic will help turn it back to healthy chalky white, it helps with curculation helping the viens to open and the blood to flow. The garlic also helps in the birds intestinal tract you should also notice that their droppings become firmer.
The Leading Online Pigeon Racing and Racing Pigeons Magazine – The Pigeon Insider