From the 70s to the 90s chimps from Twycross Zoo were used in adverts for PG Tips.
The new boss at the zoo says the chimps were "ruined for the rest of their lives".
Sharon Redrobe says they never knew how to behave with other chimps because they were raised by humans.
Zoo keepers now ensure chimps live in bigger groups.
Unilever, which owns PG Tips, says they haven't featured chimpanzees in any PG Tips advertising for over a decade and they now use the iconic 'Monkey' character as their brand ambassador.