As a general rule, what age do people start adding suppliments/vitamins to there race dogs food, i understand the added supliments depend on the dog/bitch but do you start at break in or at race age?

Please critise me if im wrong

there is no critisism, it was a question not a statement, I personally start giving them when they get pulled out of the yard and go into work

as a general rule calcium and other trace elements found in say feramo / calci d should be given from the day the pups are starting to be formed inside the bitch as too many people dont feed there pups these trace elements and end up with dogs that have brittle bones pore coat pad nail and skin health.

Than as they get older get bloods done and alter your feeding regiem from there. but a bitch in pup requires a minimum 3000 mg of calcium per day and untill a pup is 24 months old they require a minimum 2000 mg a day of calcium or there bones just simply wont hold there own. but do not exceed 1% calcium and always balance your calcium with phosphorus

Optimal levels of calcium and phosphorus in feed for growing greyhounds
calcium 0.80%
phosphorus 0.63%