This Thoroughbred didn’t win the Kentucky Derby. But he’s dominating it in ‘retirement.’

IntoMischiefhadanunremarkableracingrecordofthreewinsinsixstartsbuthehasbecomeoneofthetopsiresinThoroughbredhistory.Hisstudfeewassetatamodest$12,500whenhewasstartingoutbuthasnowclimbedto$250,000.Thestallionhassired13horsesthathaveracedintheKentuckyDerby,withtwomoreexpectedinSaturday’sracebarringalast-minutescratch.LEXINGTON,Ky.—ThemaincourtyardatSpendthriftFarmislikeamonumenttohorseracinghistory.Lookstraightaheadandyou’llseeastatuehonoringNashua,atwo-timechampioninthe1950s,positionedoverhisfinalrestingplace.WalkthroughtheU-shapedbarnafewfeetbeyondhisgraveandyou’llseeplaquescommemoratingwhereall-timegreatslikeSeattleSlewandAffirmedoncelived.Alittlefurtherout,there’sarowofgravestonesmarkingsomeofthefarm’sformerresidents,includingahorsenamedCaro,whosiredthefillyWinningColorsthatbeattheboysinthe1988KentuckyDerby. Evennow,theseidyllic,cupola-toppedstallionbarnswithwh