Often the question gets asked, at what age should you start trimming a horse’s hooves? The answer to this is not a fixed point in time, but rather depends on a number of factors and is most likely different for different horses. Ground, amount of movement, breed, hoof shape at birth, etc. all play an important role in this.
As a general rule of thumb, when the hooves start to deviate from the ideal growth and wear pattern, then it is time to intervene. Ideally that means increasing movement to promote growth stimulation and wear. However, typically that is difficult to achieve with a domestic horse, and trimming is required.
In the example pictured, this foal was born with long sloping pasterns in the front limbs. The hooves presented with Negative Palmar Angle. I advised on what to focus on, and the client started making those adjustments on the day the foal was born. This was supported by appropriate movement stimuli. 2 weeks later, I saw the filly and trimmed the hooves. Note how the pre-tim stance is already better than at DOB, and the post-trim stance is better still. The owner carried on with the trimming adjustments and 3 months later, you wouldn’t know there was a problem.
See this related post on trimming young horses.