I've never seen a U2 in the flesh, but if they're even remotely like corellas, they need a *lot* of space! My cage is 2m x 2m x 1m and I wish it were larger so Rosetta could have a longer distance to fly (beyond a couple of flaps, that is). As things are, she spends a great deal of her time rambling all over her cage, using every square millimetre of the floor space and the hanging swings and toys that dangle from the roof. She's extremely active and is great at occupying herself with her gym toys.
Smaller toys include plastic balls and baby toys (all inspected for safety and without bells) and she likes to drag those around with her as she does other stuff, like hanging from the roof upside-down. If 'Setta lived in a smaller cage, she'd probably chew a lot more than she does and might even do some damage to her cage structure. Honestly, I think your best bet is to get a Very Large Cage and then fill it with activity toys to keep birdie on the go (ie. too physically busy to think about chewing).
In the absence of that, all I can think of is to allow him out-of-cage for most of the day, encouraging him to fly around your house as much as possible. We had specific perching-stations installed for my Alexandrines at our old house so they could fly from room to room and always have somewhere to land. Sadly, the new house doesn't lend itself to that and my ingenuity's being tested all the time! :22_yikes:
