Help! Francis, one of the australorp chicks we got from Livingscape nursery, is developing stripes! She's had them roughly a week. She started out looking nearly the same, and nearly the same size as her sister-in-wings Tilly, but Tilly is much bigger and nearly solid black except for some small white patches on her face. They both have pinkish gray feet still, and have similar habits. They love to perch, and are curious and interested in people, although Tilly is much braver/bolder than Francis.
Are they both Australorps even though they look so different from each other?