I have a 3yo gelding who frets the moment other horses go out of sight , he is extremely chummy. weather i am taking the shetland out to feed him , he wont eat or even when he is with his shetland and the Welsh in the paddock beside him goes out of sight because of how the paddock is set up he is fretting. we tried removing other horses altogether for some time , but on their return, he was more fretful of them being taken away he wants to be on top of them all the time is not super respectful of staying out of there bubble space. he will pace run and scream for them, won't eat. I am not sure what would be the most appropriate way to handle this situation and teach him to not be so fretful. the horse is quiet as a lamb and a lovely horse generally. does anyone have any advice?