How old to change to adult food.

So Harley is 10 months now and were were thinking of changing him onto adult food (wainwrights). He still has enough food for another few weeks but would it be alright to change him then? Also will the adult food calm him down as his current food Barking Heads is making him more hyper we think.
Thanks

You need to change him gradually over 10 days so can start now. I left peppa on puppy food (and raw on weekends) till she was over a year old  
But 10 months is old enough to change .

You can change from 6 months, but as peppa says just do it gradually it may be the ingredients making him hyper, rather than the fact that it's puppy food. Or he may need more exercise or mental stimulation.