Victory helped Hull leapfrog Watford into the second automatic promotion spot in the Championship and the outcome was never in doubt after on-loan midfielder Boyd put the home side ahead inside a minute of his home debut with his first goal for the Tigers.
Fellow midfielder Robbie Brady released Boyd with an accurate pass and the 27-year-old rounded Blues' England U21 goalkeeper Jack Butland to tap an opener into an unguarded goal.
And in-form Egypt forward Gedo continued his rich vein of form since also signing on loan by soon doubling the hosts' advantage after Stephen Caldwell failed to deal with a forward pass 10 minutes later.
He nipped in to fire past Butland with ease before Boyd had Hull 3-0 up after 33 minutes from Ahmed Elmohamady's delivery, which ricocheted for him to shoot just beyond the keeper.
Hungary schemer Robert Koren effectively sealed the points when his shot from distance found the target, despite a touch from Butland, four minutes after the restart.
Butland did produce a point-blank save to deny Gedo but he was helpless when the Egyptian nodded Hull's fifth - his fifth goal in five games - from compatriot Elmohamady's cross (76).
Peter Lovenkrands pulled one back for Lee Clark's strugglers with a deflected shot from 25 yards with seven minutes left and Chris Burke, after Curtis Davies' effort from distance was teed back by Nikola Zigic, at least ensured the visitors finished on a high with a low drive (87).