Thanks for the reply.
They would be entirely contained within the triangular mesh, so would be unable to escape from it.
The main pen would also be completely contained by mesh, so no way for them to get out, or foxes in. (hopefully rat proof too, but that's a tall order)
If I let them free range they will be eaten within 24 hours (from
experience sadly)
I guess I'm just going to try it. If I feed them in the 'triangle' sections then I guess they'll go in there eventually.