Yes, breeding her to her son would give 75% of "her." Since you have no male duplicate of her this would be as close as you could come to replicating her. Another choice if you like her body type might be a light brown leghorn cockerel. You could take the pullets from such a cross and breed them to their half brother. When trying to create or recreate a type of chicken, numbers are the answer. Raise many chicks and select those that are closest to your goal. Each generation should bring you a little closer to the goal. It is not a single step project. Many generations are necessary.