My mare was wormed at the beginning of February. I'm moving her to a friend's closer to home where she'll be with 3 other horses. She's due worming in May, but should she be wormed upon arrival at new place?
i would say yes, my new pony arrives on sat and his current owner is worming him 2day/2moro so he's ready just to be turned out. i would check when your friends horses are due to be wormed and if you possible just worm them all together asap and carry on your worming programme for all 4 horses from then.