If Dad's an Amberlink, and mom isn't, then the chicks is a mixed breed.
Do I see faint barring? It's hard to tell in the pic, but it seem like I do. If so, the momma is the barred Rock. If not, I'm thinking the Aussie. The dominant White in the Amberlink would turn the black into white. The Red wouldn't be the momma, or the chick would have a mix of red and white.