I think pony beads are fine so long as you know for absolutely certain your bird will never ever be able to unthread them and get them into his mouth. I thread pony beads on coathanger wire, which seems to be a good diameter for them. If you do that, you have also to be absolutely certain the bird can't get to the coathanger wire by completely covering it tightly with beads. It is a toxicity risk, so be sure you understand that before proceeding. You can wrap the wire with something like thin paulie rope or fine cotton string to help cover it for safety.
Pony beads look nice strung on wire to make a swing, for example. I string them on paulie rope for my lovies and they enjoy 'counting' with them, pushing them from one end of the rope to the other. If you're strong enough, you can thread a couple onto a stainless steel split-ring along with a couple of those plastic pacifiers. This makes a nice jingly foot toy. Or, you can put a few in a clear plastic jar which you then hang from the top of the cage: it makes a nice rattle for your bird to play with (a good alternative to metal bells).
