It might keep them more busy. From my experiences hens are mentally happier with a good rooster, and a rooster will normally try to keep his hens in line. Of course there are good and bad roosters too.
It can take a few weeks before the extra protein helps. If you aren't attached to them than culling them and starting over isn't a bad idea. Once pecking is learned it can be hard to stop.
Raise your next chicks on starter than either keep them on a non medicated grower or switch to a higher...
Most pecking is caused by deficiencies and boredom. Some more information is needed to help determine the reason. What do you feed them? What is your set up like and what do your hens do all day?