Agree with Brian, do not change the kitten's food for a few weeks /months until you are very familiar with your kitten and it has settled down completely.
Minimising stress is very important and a young kitten is very vulnerable to illness, its digestive system can be shaky anyway so changing foods may be difficult for it to cope with easily.
Making sure a young kitten is eating well, means it is growing and developing, a food upset due to just changing its food can set it back a long time, as it may not be just a case of swapping the food back to the original again.
ALSO kittens need to eat a LOT, so starving it to try and get it to eat the new stuff, or a reduced intake of the new stuff, will not do it any favours either
If it ain't broke don't try and fix it.
The jury is out on what types of commercial foods are truly best for cats/kittens, so whilst Blue Wilderness may SOUND like a good food, there is no real evidence that it is any better than any other commercial cat food.
I am not saying Blue Wilderness is BAD, only we don't really know how really good it is for cats, compared to other diets long term...
There is a lot of marketing hype around grain free.
An interesting graph re grain free vs normal dog food. Reduced carbs in the grain free? Not significantly.
grainfree4_600.png
http://slimdoggy.com/worst-reasons-to-c ... rain-free/