Royal Canin Sterilised 37

Hello, my cats have been eating these kibbles for over 4 years. I never had any issues until the last order at the start of August. I noticed the kibbles are a bit bigger now. And my cats are completely ignoring them, whereas usually, as soon as I open the bag, they devour them. It's not a packaging issue. Bitiba can't do anything about it. But clearly the brand has changed something and now I'm stuck with 10kg, not knowing if I'll manage to use them up.