Change over feeding

I have been slowly changing over the pellets of my new rabbits from what they were having to science selectives I'm now doing about 40% new 60% old but they seem to be picking out the science selectives and eating them now and leaving some of the old ones is this a good thing or do I need to reduce the science selectives more (day 5) they haven't had any runny poos or anything?

I'd reduce it slightly. Another 5% and just see how they go.