hatch is a primitive that creates a provided number of identical copies of a turtle. Similar to the create-turtles primitive, it takes a number and it also allows optional rules defined for the new turtles by following it with brackets [].

ask turtles [
    if season = "spring" [
        hatch 3 [
            set size 0.1
            set shape "penguin egg"
            set color white
        ]
    ]
]

Things to keep in mind when using hatch:

• hatch can only be used by turtles within an ask statement. If you need your patches to create new turtles, you should use the sprout primitive.
• You can use hatch for custom turtle breeds, too, by using the hatch-pluralbreedname convention. For example, if your model has a penguins breed, you can use hatch-penguins and if you have an eggs breed, you can use hatch-eggs.

In the model example below, we have a turtle that represents a bug and some brown patches that represent food. When a bug bumps into a patch of food while walking around randomly, it eats the food and then hatches a new bug. Note that every time we create a new bug with the hatch primitive, we add the following command around brackets [ right random 360 ] because if we do not add this code, our new turtle would have the exact same location, size, and direction with its parent turtle, making it virtually impossible for us to differentiate the two.