I had to laugh...I tried hanging a mirror in the run one time. Every time my EE walked past it, the mirror freaked her out. A mirror in the run didn't last long at my place.:gig
That looks like a great run to me already!
If you want to do more, have you tried hanging an apple or cabbage for them to peck at? Some birds like a swing too (mine never have). I even read once of someone putting a kid's xylophone in their run for the flock to bang on. :lol: