Idaho Code § 25-1147
In deciding as to conflicts of brands, the state brand inspector shall reject any brand being the same as one previously recorded in the same place on any animal; it shall also reject all brands known as solid brands and the window sash brand. A variation in the size of a letter, number or figure shall not constitute a new brand and shall be rejected. Combinations of letters, numbers or figures may be permitted, though the same letter, number or figure may have been recorded singly or together, if in the judgment of the state brand inspector, said combination is so different from any previous record as to constitute a new brand with no danger of infringement. The inspector shall have the right to reject any brand that may in his judgment endanger infringement of the previously recorded brand.
Idaho Code § 25-1147