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?
Increase the distance from each other in a pen further away, using the same process above. If you have two or three pens, you could eventually have them separated by increasing distances with the horse still not fretting.
Separate them for maybe a few hours then bring them back, repeating the process while each time, separating them longer, but bringing them back afterwards. Each time in the process, try getting relaxation through a change in focus each time in the separation process.