There are no specialty kitten mice in the wild, and some dry foods like Wellness Chicken Kitten and Wellness Chicken Adult are for all intents and purposes identical (same fat/protein/mag/ash/etc and 99.9% identical ingredients list).
Kittens simply require more calories and higher protein/fat percentages of their diet to maximize their growth, and many indoor adult diets don't offer that especially the lower tier brands.
Wilderness on the other hand does, so I would consider it a "all life stages" food. I am feeding their dry formula to mine, and they seem to really like it. For wet, we were doing Wellness chicken until they got bored with it, now we do a bit of everything as long as its rich and has quality ingredients.
BTW, and it may just be that they outgrew it, but the Blue Buffalo kitten chicken and rice formula resulted in soft stools for us, verified when finishing the bag after another slow transition, but Wilderness isn't. They both also have those "lifesource" bits and I can't tell a difference, but they would always eat around them in the kitten formula but not in the wilderness, so perhaps even those are formulated differently. Just get a small bag either way and go nice and slow. With petsmart, if it doesn't take, they even let you return the bag for a refund though which I thought was just fantastic policy, so I always recommend them.
Yeah, he'll be fine. As long as he eats the "lifesource bits", because that's where they put all the vitamins in the food. Some cats won't eat those, the stinkers!
What Does the AFFCO statement say? If it says all life stages or for growth and maintence then yes it is fine...3 out of 4 wild kittens do not survive more than 12 weeks thus dont need kitten mice
I too noticed the lifesource bits in wilderness were not left but I think it was the reformulation as the old one mine all left them...