Cant agree with the wind bit Stuart as they’re winning sections/feds around here on the same day both north and south, both cant have the wind up their bottles.
Perhaps the nearer to their origins they get the better they perform ;D
In the fed I race in there’s no doubt that youngsters benefit from being given 4-5 races, if you were in my fed I'd advise you to stop them after same.
If your racing your youngsters on the so called natural system (not darkness) be careful not to send them whilst bald around the head also when they’re losing the cover feathers on their wings.
Not necessary the case mickb, there was something similar happening to pigeons a few years back which affected both young and old birds, a form of Herpesvirus was diagnosed.
The y/birds will body moult but hold back the throwing of flights during this darkening period whereas y/birds left on natural daylight will moult and throw flights throughout the y/bird season.
See if you can contact this Vet
http://www.poultryhealthcentre.com/mainpages/practice.htm
by email:- dgp@poultryhealthcentre.com
by mobile and text:- 07811 155387
You could mix Gemthepax on their feed BUT I would double check with the Vet first. Dont put anything else in the drinker bar their medication as this could have an affect on how much they drink.