They've spent all day today together outside in our large run which was the biggest foldable run I could find when I got it a few weeks ago - lots of room for them to run around and get away from each other.
I started off with nowhere at all for them to hide. If it was a scratch from a squabble rather than an accident, my guess is it came from our dominant sow, Red Lazer. She immediately went up to new girl (yep still nameless!) and tried to nip and push her around. Strong (classic) dominant behaviour but nothing that was causing any damage. I stayed keeping a very close eye. It lasted about 5 minutes before Red Lazer got bored of it and started eating grass instead.
Fizz and Nibbles paid no attention to new girl particularly.
After a while watching I needed to provide some extra shade so I hung two old towels either end of the run which gave loads of shade and also hideys but impossible to block access in or out (thanks for that idea
@Wiebke usually I just put them on the outside to create shade).
Nibbles was ecstatic about this development. She careered around and popcorned like mad for ages! They all enjoyed it.
New girl doesn't particularly try and stay away from Red Lazer but I haven't caught them near each other at any point.
At one point today the other three wee sitting one end of the run and new girl looked very little all by herself at the other end but they've all moved round lot through the day.
The 3 are not a close group - the sister pair we have spend a lot of time cuddled up to each other, these three do that infrequently so I'm not looking for close snuggles just for them to live happily in each other's company. They seem to have achieved that today - by the end of the day they are all moving around, munching grass and hay and new girl doesn't appear to be experiencing any more dominance than Fizz or Nibbles have to put up with!
Thanks all for the support and suggestions. Means a lot to me.