Oh I'm so sorry!!
I do thank you for the warning too.
I've been letting 2 of my girls stay in the play pen when I run to to store.
And I've been letting my new 10 week old stay in the cage with one of the other girls. Until I read this.
They have never showed any aggression to one another at all but I don't leave them together unless I'm in the room.
Especially the baby because she is really shy around the other girls. So if they wanted to start something I don't know if she would even try to defend herself.
And I'm very sorry for you loss.