Personally, I prefer to maintain feeding the same quantity year round and therefore will vary the quality of food with regard to protein and fat content, depending upon the work I expect my dog to perform. I believe that fat content, and its ability to maintain energy levels, is an asset to scenting abilities of dogs. A tired brain and a tired body make for a tired nose. I have found that during peak performance, the higher the 'octane' of food that will keep a dog going and concentrating, the better or longer-lasting will be his scenting abilities. Just prior to any competition, if you want to feed your dog, give a much smaller quantity of food at least two hours before starting to work.
Retrievers run mostly in straight lines during their trials.
On the other hand, Coonhounds have to be able to work in some very tough undergrowth and marshland where staying power and physical resilience is of paramount importance. All potential circumstances in the field must be carefully prepared for, especially the demands of whatever activity your dog will have to face. The temperature, humidity, type of ground and cover, and game he has to handle are all variables for which you need to plan. Acclimatization is essential and many owners who have their dogs with them in an air-conditioned house during the summer make the mistake of bringing them out to perform immediately in the cold waters of the north or the heat of the day. The shock to the system and their health is too dramatic and although many may feel guilty at using outside kennels or runs, this is often the only practical way of acclimatizing your dog.