In A New Hope, Kenobi could feel the sudden deaths of the population of Alderaan, and in Empire Strikes Back, both the Emperor and Vader could feel Luke's Force awakening, referring to it as "a great disturbance in the Force", and that was only one person!
So wouldn't creating millions or billions of clones for the Republic's armies create enormous and weird disturbances in the Force? Why couldn't the Jedi sense something so unnatural on such a vast scale, especially considering there were many Knights and Masters? Surely somebody would've noticed something!?
(I know this is based on a (possibly unfounded) assumption that breeding an exact clone of a living thing would generate strange vibes in the Force, somewhat akin to the impact Luuke Skywalker had on Luke in Heir to the Empire etc. An EU concept, neither confirmed nor denied in canon! Either way, you'd think that logically a planetload of a single individual, Jango Unlimited, would not be a normal happenstance within the Force.)