Footiness is a symptom of less than perfect health. Sometimes only minor, sometimes something more. But less than perfect health nevertheless.
This is a quick list of things to consider:
- too much grass
- impact on grass of change in environment (rain after drought, several days of frost, fertilizer)
- too much sugary/starchy feed
- sugary hay (for cool season grasses)
- other non specific dietary upset
- course of antibiotics
- abscess brewing
- sole been thinned by inappropriate trimming
- foot overdue for trimming
But please don't be tempted to shoe until you know what the problem is - you may resolve the footy symptom, but you won't resolve the cause and without the footiness to guide you, you won't know if your horse has been restored to better health.
If you are determined to shoe (and of course I'd counsel against) then only shoe a sound horse.