Good information Owen,as you say Colin Walkers book gives some info (I have the Book). Before Gary Spavin started up I used to go to Raymond Ingrhams who Gary aquired the business off,always a coffee on while you watched him test,he talked you through the procedure while he done front and rear swabs and showed you the results on a TV. screen,later you phoned him for the droppings results.Gary does exactly the same. There are herbs,tinctures and tonics which he sells be he never pushes them. http://www.auspigeonco.com.au/ Lindsay