An Ageable Entity is one that grows over time, like a cow.

Importing the package

Link to importing-the-package

It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import.
import crafttweaker.entity.IEntityAgeable;

IEntityAgeable extends IEntityCreature. That means all functions available to IEntities also are available to IEntityAgeable.

ZenGetters/Setters

Link to zengetterssetters

ZenGetterZenSetterType
ZenGetter
growingAge
ZenSetter
growingAge
Type
int
ZenGetter
ZenSetter
scaleForAge
Type
bool

Methods expect an int and the second method an optional bool.
Both methods return nothing.
Normally, the second method does the same as the first with false as forced argument, that may differ for mod implementations, though.

ZenScript
Copy
entAgObj.ageUp(int seconds, @Optional boolean forced);
entAgObj.addGrowth(int seconds);