You can try probiotics or yogurt, electrolytes and Medicated feed. If it's mild this may take care of it.
If not you may be dealing with coccidia and will need to treat with Corid.
OK, I was curious. :)
You were right about how they like to peck at red things. Just keep an eye on them in case they decide to peck again. It may take a day or two for it to heal. :)
It's best to isolate the one with the hurt foot away from the other birds for a couple days until it heals. I've had to do this before with mine a couple months ago. You can also put a little triple antibiotic on it to help it heal. :)