Dodo

The Dodo Egg is the Rare-rarity egg of the Prehistoric, and the pet inside it is Dodo. Prehistoric is zone 8 of 11 on the normal route; the wiki lists its entry requirement as ~17M–18M speed, and the nests there are watched by the T-Rex.

Base income is $280/s. Among the 8 pets tagged Prehistoric on the wiki that puts Dodo at number 8 — Mosasaurus tops the Prehistoric at $180M/s. Remember the game multiplies this base by the size roll and by the mutation, so two Dodos can earn very different amounts.

With a colour mutation and no size bonus, the same Dodo would earn roughly: Silver ×1.2 ≈ $336/s, Golden ×2.5 ≈ $700/s, Rainbow ×3.5 ≈ $980/s (multipliers from the wiki's Mutations page; arithmetic is ours). Add a Giant (×3) or Huge (×5) size roll on top and the numbers multiply again.

Hatching it pays a one-off reward of +240k Speed, $28k, and the egg takes 1m 30s to grow in the pen. That reward is the reason low-income eggs are still worth stealing early: the speed bonus is what gets you into the next zone.

A Rare is usually the first egg in a zone that is worth waiting out the 5-minute nest reset for.