Yes. This means, if the mother is pure for the white skin gene, she will NEVER produce a chick with yellow feet, no matter who the father is.Australorps should have white skin -- which is a dominant trait.
So either the chick does have white feet (genetically speaking, but they might look yellow at hatch like the other chick someone posted.)
Or if the chick really does have yellow feet, then the mother has the gene for yellow feet, which a pure Australorp is not supposed to have. It is possible for a chicken to have white feet but carry the gene for yellow feet without showing it, which is what might be happening with that hen.