After RBTAs split, it takes them awhile to regrow mouths. Until they do that, they are still healing and don't eat...can't eat actually. It's pretty common for them to take up to 4 weeks to totally heal. Until you see that they've reformed mouths, don't attempt to feed them. Once you see the mouths, definitely feed them.
I believe it's actually a misconception that our clowns actually feed their anemones. It's been shown that it actually never happens in nature and while it does appear to happen in our tanks, it doesn't seem to be a purposeful thing on the part of the clowns...and also doesn't appear to be something that happens regularly enough to actually be of nutritional value to our anemones.
With the right amount of lighting, our anemones normally don't need to feed but it never hurts to supplement them with regular feedings. My RBTAs get fed at least 3 times per week.