They wrote that into the Second Movie, one of the characters or extras had the same thing happen to him that happened to Hammond in the first Book. They really butchered the first film, although I enjoyed when it came out.
and they used the aviary in the 3rd movie, along with the scene of what was to be the Tyrannosaur swimming like a crocodile.
the effect were amazing at the time, and all wow, but it would have also cost $1,000,000,000 to make it like that book then.
Anyone who liked the Jurassic movies should really read the books.