Unlike all the other stats, agility never averages together. I can mix a pet with 100 agility with a 250 agility pet and the resulting pet will only have something like 117 agility. Mixing agility seems entirely bugged and I don't know if it is just like that on my account or on everyone's. If it is just on mine I need to send in a ticket to have my account fixed, if it is on everyone's then I should only have to bring it up here. It doesn't matter which character of mine I mix pets on, agility always comes back with very low stats.