Are there specific problems associated with feedlot horses? Having absolutely no experience of 'feed lots' or horses from that persuasion, this post reads to me like... "I want to know what I can do with an untrained horse & what problems there will be". Sounds like you don't have any experience with training horses? If so, I would be looking to have your boss or other hands-on mentor to teach/supervise. It's too broad & skilled a subject that you can learn enough from the internet for & untrained horses are easily ruined with 'wrong' training.