We had the same problem with our girls and an extra rooster (who is now gone). The feathers are slowly coming back in. I bought 2 chicken aprons (saddles) on ebay. I'm using one on a hen right now and the other is sitting on my sewing table waiting to be used as a pattern. I agree that they look pretty easy to sew together. If I ever get some extra time to get mine made I'll post a pic of them (although by then all the feathers will probably have grown back!)can you let the roosters free range in another area, even if they don't have access to the coop during the day.
Some places like ebay sell cheap saddles, they can be pricey from the hatchery. I think there are threads on here that sell home made saddles. I'm sure once you got a few you could even make you own, they don't look that complicated.