Yup my little 24yr old Connie x mare is casting already and always does in August. When she was in hard work I had to clip her in September. She does though cast her coat very quickly in spring and all the clip lines have gone before everything else on the yard.
my old boy is- he's nearly in his winter coat already!! strangely enough, the TB hasn't started yet, and in the past he has got his coat before the oldie!!!