Hi Debs65
Well done having three hogs visiting already. Re. the hog igloo. The best thing to do is find a suitable site that you are really happy with and then leave it there. Sometimes hogs will use one quite quickly, but other times, they may not use it for as much as a couple of years, by which time it has become part of the landscape. So don’t be tempted to keep moving it. Hopefully you will be lucky and a hog will use it quickly.
You might like to put a small amount of bedding in, to give them the idea, i.e. dried leaves, grasses, hay, etc. but most hogs like to do their own interior decoration so leave a pile of suitable bedding nearby so that it’s easy for them to choose what they want to build a nest inside the hog igloo.
Good luck. Hope you get a tenant soon.
P.S. Hopefully you are leaving out a good supply of water for the hogs, too – Ideally all day every day.