Question: If the Wolf, the Ape, and the Croc were all exposed to the chemical around the same time, then why is it that the Croc grew to almost triple the size of the other two by the time they hit the city? The ape is bigger than the croc at normal sizes and the wolf is more or less the same size. So why did the croc get that much bigger than the other two?
Question: Why did they have to call a stealth bomber all the way from Missouri to go to Wyoming to bomb the creatures? There is an air force base in Wyoming. And secondly, why even need a stealth bomber? they are targeting animals in an already heavily publicized event.
Answer: Likely because the bomber was prepared with the necessary payload, compared to any in Wyoming.
Answer: The Wyoming Base most likely did not have the ordinance or aircraft capable of carrying the ordinance required so they used the closed base with the available ordinance and aircraft. Not every base has the same ordinance and aircraft at the same time.
Answer: Perhaps the chemical has different effects on the animals that it is being exposed to, and the crocodile was mutated into a much bigger size than the gorilla and wolf. I don't think the movie is really expecting anyone to question this, but is really just done to give the protagonists an opponent to face.
Casual Person