The zoo at Johnsons of Old Hurst is in the Cambridgeshire village of Old Hurst, north of Huntingdon, and has more than 100 animals including lions and tigers.
The fully licensed site includes a farm, cafe and butcher’s shop, which opened 20 years ago, while its crocodile house was built in 2009.
Visitors can see Nile crocodiles, broad-snouted caiman and American alligators, which are kept in a converted barn with metal-fenced, elevated walkways.
Mike Annicelli, 52, lives near the zoo and said the crocodiles were about 15ft (4.5m) below the “raised platform”.
A woman who visited on Thursday said the crocodile enclosure included “quite high fences” and said there was “steel mesh fencing” all around the viewing platform.
She said the crocodiles appeared calm and largely motionless during her visit, about 10 minutes before the incident happened.