Unless it's a sex-linked breed, you can tell when they are first hatched and then you have to wait until it starts acting like a pullet or cockerel. If it starts growing spurs, you can be sure. For your sake, I hope it's a hen; australorps are good layers.

Hens are the bigger chickens where the rooster are the smaller more slender chickens with a little crown on their head.

It's cute.

That's all i can tell.

Look at the front tail feathers. If they're pointy, its a roostin rooster

If theyre rounded, its a henny hen.

Hen Don't look like no rooster to me.

I really need to know