With youngsters what you have to avoid is sending them with food in their crops. There's two reasons for this, 1) they'll throw up in the basket, 2) YBS can strike overnight, if fed correctly their crops should be flat as a pancake...........if not they're holding food which = YBS. I suggest you feed them 3/4 of their normal ration on a Thursday & 1/2 ration Friday morning, come basketing if healthy no food will be felt in their crops. As for water on return from a race plain water is the best thing you can give them. Lactic acid plus other impurities build up in their body's during the race and this gets flushed out of their body's via kidneys & liver, anything added to the drinking water hinders this process.