I am also a novice, but to me it sounds like they are molting....have you noticed any other changes in behavior or a decline in egg production? my EE molted last year (in the fall which is typical due to the decreasing light) and the others did not, almost all of the feathers on her neck were missing and many on her body were ragged but did not fall out much. She stopped laying at that time as well. Molting is normal but the red skin sounds like it could be cause for more concern though. My chicken's skin looked normal while she molted but I was very concerned at the time because I had never experienced it before. She did not resume laying until early in the spring.
It is a good idea to increase calcium and protein in their diet when they are molting as growing new feathers requires a lot of energy and molting can be stressful on the bird. I would instinctively think it would also be very important for them to have constant access to clean water during this time especially when it is hot. A good source of calcium and protein is yogurt (i give mine plain yogurt because a lot of sugar is not good) and they love it.
Hope this helps
