If you like taking chicks outside, starting sooner is just as good as starting later, and might even be better.Okay, thank you. I don't mind waiting until they get older. I am in no rush. I can wait until they are 4 weeks old. In the meantime I can work on fencing off their area, adding another gate and maybe getting a chicken shed instead.
If you do not like carrying chicks back and forth, you can gradually reduce the heat in their current brooder until they are living at or below the outdoor temperature, then carry them to the outdoor coop and leave them there.
And it's also fine to take them outside one day but skip another day, based on when you just feel like doing it.