Through naturalization records, I learned that one additional brother had emigrated to the United States. I learned this because the microfilm records are in order of naturalization at the court. As I looked up the records for the Hofmann family that I knew about, I also looked at the other people that came before and after. That was how I found another brother.
Later I found still another brother through census records. Then I checked his naturalization papers and it turned out that he had emigrated four years earlier and joined the family after they had arrived.