There's a pretty wide range:

Mac & Ozzy are just barely 1

Delta, Antare, Raven, Chase, Pacer, Founder, Chum are all around three.

Heyoka is probably about four. Franklin is four and a half.

Pingo, Bandit and Hobo are seven.

Muskwa is six.

Kayleigh and Earle are five.

Goldie is a complete guess, but I think she's about six.

Sleet and Preacher are both about ten.