Adding two created_at on one insert

I want to add another created_at column on the database columns for reference.

I want to have a created_at and created_at1 at the same time.

This is what I have in my Model:

const CREATED_AT = 'created_at1';

protected $dates = [created_at, created_at1];

But I'm receiving this error: Field 'created_at' doesn't have a default value.

via Chebli Mohamed