Ah... ok... well he's almost through the bag now, so I'll look into something better and start mixing the two for a week or so to get him used to the new brand... 
I live in Canada so I'm not sure what's available here and if I'll be able to buy any of those brands, but I'll start looking around..  
Thanks again for the info's everyone 
 
xoxMolls&Tobyxox