If he's been on the Mazuri, I would return theTimothy Complete and buy the Mazuri. He shouldn't be switcheddrastically, but rather slowly and over the course of a week or so.
I will say though, that Timothy Complete is a good food. Harper's on itbecause he does much better on a Timothy hay based pellet. It also hasa higher fiber content than alfalfa based pellets.
Even if the mazuri is Timothy-based, it does have other things that areprobably different (percentages of things, and some such), so switchingsuddenly could cause your bunny to get diarrhea. Best toswitch gradually.
Here's a good, easy way to do it:
First week: 1/4 new food to 3/4 old food
Second week: 1/2 and 1/2
Third week: 3/4 new food to 1/4 old food
Fourth week: a complete amount of the new food
Hope that helps!
Rosie*
P.S. Or you could just return the accidentally-bought Timothy and get the Mazuri.