Yes, they sell pellets for a reason, less waste and they don't have to pass the pellets through the crumbler.
If you read the chart on the back of your feed bag, it will tell you what feeds they make that are appropriate for your birds' ages.
For each type of feed, there is no difference in nutrition between crumbles and pellets. They're the same feed.
If you're talking about switching to layer feed, that's a different story.
You'd be pushing it this time of year switching to layer with birds that age.
There are all-flock pellets that are basically the same thing as start & grow crumbles.