Oldest to Youngest

[StrutEggStealer]

She says it in the Mysterious Island, look up at my original post.
IDk if she says it again, but she does mention hatchday several times in that sequel

[Bruton the Iguanodon]

Ducky is the first we see hatch in the original, but Cera claims she's oldest in 5. Me? I say Petrie is the oldest!   He's my favorite, and the idea of him hatching before movie 1 begins is a good justification for why we don't see it.