Ok i have many natural attacks (bite, claws and gore) with an amulet of mighty fists +1 agile i increase attack roll and damage and apply DEX instead STR with ALL my natural attacks?
But yes, a +1 AoMF would grant you a +1 to attack and damage, and the Agile enchant would allow you to cause +Dex to dmg with each attack instead of +Str to dmg.
Also, you would need Weapon Finesse in Natural Attacks for an Agile Enchant to apply.
You just need the Weapon Finesse feat (and the agile amulet of mighty fists for this to work, weird class abilities faking Weapon Finesse notwithstanding. The feat itself doesn't require selecting a particular weapon or weapon group.
Remember that, unlike magic weapons, the amulet doesn't need to be +1 to have the Agile property. This means that you can get an Agile AomF for just 4000gp.