Picture of his feet, top & bottom please.
Separate the Roo from the hens until his feet heals.
Have you checked his feet if there's something that the hens see and keep pecking at it?
Welcome to BYC. Liberally apply Nu-Stock to your roosters feet. Once your hens get a mouthful of Nu-Stock, they wont pick feet anymore. Shake the tube well and wear disposable gloves when applying it. It can be found in the Equine section at a feed store. It will also heal your roosters feet.
Nustock is good, and I have heard others who have had good luck with Bag Balm, Pine Tar, and even plain Vaseline use for pecking because of the stickiness or bad taste. Nustock is antifungal and healing, so a good choice.