just back to sport after 35 years . but i think a lot of the problems are with overcrowding , doseing birds up for this and that . i think like anything in this world they need to get dirty and build an immune system up. every thing seams to be chemicals for this that and tother. we are all looking for a system for getting an edge , everything on winning at any cost, surely we should try & get back to basics , i think a good fit &healthy bird should fight most things given time . i except some virus are worse than others and need treating , dont mean to try & tell you lads anything as i am sure you have much more experience than me , just an oppinion .