Australorp chickens are large, black, single-combed birds with clean, unfeathered legs. They were developed in Australia in the early 1900s and are valued as both an egg layer and for meat. They have a bright-red waddle, comb and eye ring and black legs, eyes and feet. A mild-tempered bird, the Australorp is very cold-hardy, and is well-suited for the urban farmer. You should be able to sex your Australorp rooster before it begins to crow by looking at developing anatomical differences. You can't sex birds as you do mammals because their sex organs are internal.
Examine the blade of the comb which is the lobe-like area at the rear of the comb. Roosters have rounded blades nearly half the length of the comb. Female Australorp chickens have combs that only cover two-thirds of the head and end in a sharp point.
Check the red waddle of the bird. The Australorp rooster has a waddle that is longer than it is wide. The Australorp hen has a waddle that is wider, or as wide as, it is long.
Examine the neck plumage of the chicken. Males Australorps have pointy neck plumage that cascades over the shoulder and down to the beginning of the wing. Female neck plumage reaches the shoulder and is rounded.
Observe the tail of the chicken. The tail feathers of male Australorp chickens cascade in a soft rounded waterfall effect. Australorp hens have blunt, short tail feathers.
Listen to the birds. The roosters will crow while the hens do not.
For information on vent checking of chicks see the resources.
Vent sexing chicks can increase chick mortality.