Judith,

two of our horses are doin this exact same thang, they've been on the place for 5 or more years.  Never done it like this before, but both of them are prone to rain scald moreso than any of our other horses. Don't know why, they are on good mineral, and feed. So...who knows. They've both been wormed regularly, and just since it's warmed up and they started sheadin out "normal" or so I thought, when I started brushing them....more and more hair came out. neck, withers, and butt all almost naked of hair. You can see new hair growin back now. I asked a neighbor about it, and she said she's had horses do that too, and never could find out why. These two were wormed a couple weeks ago, and will get it again tomorrow, just in case there's somethin that the first dose(safeguard) didnt get.

 :???: