hives? beatpulp

[Shimmeringshoes3@cs.com]

I started my 10 year old chestnut arab gelding on one lb beat pulp and one 1 
lb equine senior am and pm everyday approx. two weeks ago. for the past week 
he has had crusty yellow sores around his flank area and sheath area. I 
believed it was fly bites because the little knats and flys appeared right 
around the same time. Tonight ( I just returned from my visit with my horses 
) he appears to have hives all up and down his sides. He has also been some 
what more pushy recently and very excited about his food. I also feed grass 
hay (20-30 lbs per horse daily) but since I have started to give him his 
(treats) he has been very demanding. Testy to be exact. I believe he is 
irritated.I think he is having a allergic reaction to either the beat pulp or 
the equine senior. Has anyone experienced this? I feel that I should 
elimanate both products and see what happens. Maybe it is the molassis??  If 
anyone has any insight on this please share with me . Thanks Linda ( been 
envolved one way or another with endurance since 1980 (1000 miles)