Purchasing previously owned adult pack goats may work in some cases however, your string will likely be fraught with issues. People selling 3-year-old + goats are not selling them because they are awesome packers (unless they are “getting out of goats” and selling their whole string.)
You will likely be buying another packers difficult goats (which are hard or impossible to make work) or a person’s pet, who is untrained and has lived his whole life in a pasture, out of shape and learning to be lazy. A goat that has lived his whole life in a pasture will not be agile or have trail savvy. Be prepared to have about a 30% success rate buying adults that will make good packers.
We recommend starting with babies to create a bond, begin training and conditioning from the start. It doesn’t take long before you will be able to put about 10% on them in the summer of their 2nd year, 20% in the 3rd year and full loads in the 4th.
Also, please buy your stock from a proven packer breeder…Every dairy operation in the country tries to sell their bucklings off as packers or meat. They often do not have the proper size, conformation, or temperament. The biggest mistake I see new packers make is buying junk goats from their neighbor or craigslist.