thinning mane and tail

Question
Hi, I have a 6 yr old Rocky Mountain gelding that I bought about a year ago.  When I got him, his mane and tail were full and long, but over the past 5 months he's started rubbing and has gotten some raw spots under his mane, at the base of the mane, and at the top of his tail.  The mane and tail as a whole have been thinning also, even his forelock.  I deworm every 2 months with paste wormers, so I don't think parasites are a problem.  He did have some sensitivity to flies this summer, so I've been keeping a fly sheet and hood on him.  He hasn't lost weight, and the rest of his coat looks good, but I'm going crazy trying to figure out why the thinning mane and tail.  I've tried using MTG, which didn't seem to do anything, and I've been rubbing tea tree oil (and alternately aloe vera vet cream) into the raw spots on mane and tail.  Any suggestions?  Oh, I also use Grand Coat in his feed.  Thanks for any tips!

Answer
hi Denise,
i have the same problem with my filly. what they do it they put their head inbetween the fence to get more food or grass. its normal and many horses do it. i would put something up to make it so he cant put his head through the fence. horse wire is a good choice. they cant get stuck in it and it is 100% safe. good luck
amanda groff