A duly executed bill of sale is an instrument in writing by which the legal owner or authorized agent transfers to the buyer the title of livestock. It should include the following information about the animal sold: for horses or mules, age, color, and sex, with special markings; for registered cattle, registration number tattooed in ear, name, sex, breed, brand, and marks, if any; for range cattle, sex, age, breed, brands or earmarks, wattle or dewlap.
Both the seller and the buyer shall sign the bill of sale, giving the post-office address of each, in the presence of a witness, who also signs with his name and address and who is a legal resident of the county where the transfer of the described livestock takes place. The bill of sale shall be dated the day of the transaction.
2021 Colorado Code, Title 35, article 54, § 35-54-103.