Your friend is likely referring to Scratches, when she is showing you the healing sores. Yes draft feather can be a lot of work and some clyde and shire people (who show) wash legs daily and then rub them down with sulfur powder after (sulfur is a good anti fungal and 'dries' up the scratches scabs). Some also mix the sulfur with mineral oil and apply to dry legs- the oil softens the scabs and makes them easier to pull off and sulfur "dries up" the sore. The washing will prevent yellowing of white feather. You wouldn't need to go to this extreme, unless you show and would like WHITE white feather...
Any horse is susceptable to scratches, but it is definatly more prevelent in our feathered friends. My favorite remedies include Desitin (otc cream for diaper rash) and my very favorite is M-T-G. MTG is sulfur and mineral oil, plus a couple extra anti-fungal ingredients. It's handy to have for any itchy horses issues, too.
I would NOT recommend wrapping- the key is to keep the legs clean and dry, and that includes the horse bedding.
Some cases are more difficult to treat than others, it just depends on the severity. If the scratches are real bad, it will take patience and daily treatment to get it cleaned up.
I usually check my horses legs on a weekly basis and if there is a flare up, I am usually able to get it treated before it gets too bad.
There is more information out there on scratches- maybe try googling it or visiting the draft horse forums for more details.