As barefoot horses become more popular, which is awesome for the horses! More and more barefoot trimmers are getting into the business. Most have had lots of training and experience and are very good at what the do. Some are not as well trained or experienced and not so good at what they do. It's a horse owner's responsibility to pick up their horse's hooves and examine them frequently and ask questions if what they see doesn't appear to be right. Just as there are good and poor farriers/horseshoers, we are all hoof care professionals and some don't have the knack for it that others do.
Some don't recognize hoof issues like founder and abscesses and hoof ailments are often misdiagnosed so it's the owners responsibility to determine when a veterinarian should be called in to check their horses.
Hoof care professionals, in some cases may know more than your vet about hoof related illnesses, but we are NOT veterinarians and it's not even legal in the state of Washington for hoofcare professional to diagnose problems like laminitis/founder. If we suspect serious hoof issues, we need to recommend a vet be called in.
I have to write this because I'm seeing so much of the opposite going on and walking into cases with horses who have been under a farrier or trimmers care for months even years and finding issues that are usually associated with serious neglect.
Ultimately the horse's hoof care is the owner's responsibility. If you don't like what you're seeing call for a second opinion. If that bothers your hoof care professional, replace him/her. Second opinions are typical in other fields and we shouldn't feel guilty about making sure our horses are getting the best care possible and that our money isn't being wasted on anything less. If your trimmer/shoer objects, get's angry and quits, or assures you that they already know it all, then they don't know what they don't know and they are the most dangerous ones to have working on your horses!