This is not the 19th century. There is no need to produce 25 rideable horses by sundown tonight. A horse 'brought on' in an environment that produces a horse that wants to learn makes a horse that will be a pleasure for life. This may take a little longer, but the rewards are well worth it. Horse ownership is a privilege and brings with it a great deal of responsibility.
Horses are herd animals and do better with company.
If there is no company, then they should be kept where there is plenty going on. But, they still need regular visits from people for grooming, hugs and scratches. Horses respond better to patience, love, patience, respect and patience than they do to almost anything else. You do not have to send your horse away to be trained. We will come to your house.