What would cause all exhaust valves to stick open?

Bent valve, collapsed spring, valve stem seized to valve guide.

True, CamaroCollector but ALL of them? It has either a 2.4L.. ..a 2.7L or 3.4 - V6. And every one of the are 4-valve per cylinder engines. So the V6 has 12 valves stuck open? All on the same cam. If the timing belt broke, and the V6 in '03 does have a belt, they would be frozen in position with some open some closed and maybe some in between..but all of them stuck open> Something doesn't sound right

i read it to fast and missed the word ALL, but if it's an interference motor it's still a possibility

Ok, righto. I see what you mean. It spun a few times and every turn another valve will bend and stay there

It has 2.4 and it has a timing chain. Intake side is working correctly. Is my next step to remove the head?

Yup, Valve job with new valves.

And maybe a new cam, cam bearing, chain, tensioner... depending on why it happened in the first place ....to keep it from happening again. I don't mean all those parts but what went wrong to cause it