My guinea pigs don't want to eat their new pellets (it's more like granules I think). I tried to mix them with the old ones but they only eat the old pellets. They just sniff the pellets and don't try to eat them (I have to admit, those pellets have really strong smell). I bought a big pack and now I don't know what to do with them. 
This is the brand I am talking about:

What should I do? Should I let them be and maybe they'll get use to them or I have to buy them only the old pellets?

This is the brand I am talking about:

What should I do? Should I let them be and maybe they'll get use to them or I have to buy them only the old pellets?