What nuts are small amazons able to crack?

[Elysian]

I want Opie to have some snacks and treats that are more of a challenge/activity for him, so I bought a small bag of mixed nuts for parrots.
I'm not much of a nut eater myself so I didn't think through what the shells would be like

Almond was no problem, he tore that open immediately
I tried a hazelnut because they were small but I see now that he can't get into it because it's too smooth or hard.
Haven't tried the walnuts, they look like they could be too big for him
And the last thing in the bag are pecans, haven't given him one of those yet but they also look a little smooth.

Has anyone worked out a challenge/skill level gradient for nuts so I can belp him work his way up?

 

[Hankmacaw]

Pistachios are good and you could probably crack a walnut is a few places so he can get into it.

 

[macawpower58]

Possibly an almond. My Mealy loves them, and even my Goffin can crack them open.

 

[Mizzely]

My Jardine's is able to cracks, pecans, almonds, pistachios, and pine nuts. Walnuts I crack in half and give him half...getting the meat out of the shell is still fun

 

[Clueless]

My guys loved pistachios

Their first toy was little pops with handles. MC so loved these toys with pine nuts. The owners of this company are good friends of mine (that I met after adopting my Amazons).

Parrots Treasure-Foot Toys

 

[iamwhoiam]

Almonds, pine nuts and possibly walnuts. My Amazons can generally crack walnuts but sometimes they need assistance.

 

[PatrickDov]

My Amazon absolutely goes nuts (no pun) for Pistachios!

 

[MR. Mango]

Can’t really help with this, mango gets the easy pre shelled stuff . . . Bedsides he’s such a tiny birdie . . . Plus he’d probably give up