I'm looking at buying a horse, but have some things to consider pre-purchase. My concern is with integrating him into the herd. We have a make shift "arena" type concept we've put up until we can have one built. It's made out of hot tape and those white things you stick in the ground with (capped) T-Posts for the corners to keep it tight. It's four feet high. It shares a fence with our pasture, so this is where he would go to meet the herd. My concern is that this will not be safe enough to leave him in for extended periods of time or overnight. I feel like I have seen horses contained in this fashion before, but I'm really unsure. We don't really have another area to put him in to introduce him overnight. The other pastures are quite far away, and I don't like the idea of him being in a stall alone in the barn all night.
Am I just being paranoid/overly cautious, or is that an unsafe situation?