Lovely photos. I'm surprised they swim them for half an hour though. When I took my horse to an equine swim pool for his rehab on his check ligament he was only allowed to do 3 laps on each rein the first time, and then built up an extra two laps every week, to a maximum of 8 or 10. That would have been a whole fifteen minutes, twenty max and that was with him going week after week. It is extremely tiring on the horse. I heard of an old swim pool by me and the owner had a horse they wanted 'rid of'. The insurance wouldn't pay out on its injury which had given a very poor prognosis of ever being able to be ridden again so the owner of the pool at the time swam the horse to death. It was forced to swim for so long it was totally exhausted which brought on a heart attack and death. Of course he got his insurance money for it then.
Totally disgusting act, if its true what I heard that is.