Sure sounds like molting.
What causes the regular fall molt is the days getting shorter, not temperatures. In Delaware you have lost about an hour and a half of daylight since your summer solstice, from about 15 hours of sunlight a day to 13-1/2 hours today. Most chickens tend to wait until a little later in the season to molt but 1-1/2 hours of getting shorter is substantial. I've had a broody hen start the molt early also so that might factor in with that one hen. It is very possible also that only some of your hens have started the molt.
Not in my opinion but a lot of people I respect on this forum disagree. In nature, with a feral flock, the hens stop laying eggs when they molt. The nutrients that were going to egg production are diverted to making new feathers. Nature took care of that.
Some people think increasing the protein content of their food will get them through the molt faster. Again, I disagree. What controls the speed of the molt is not how fast the feathers grow back, it is how fast they fall out. That is controlled by genetics. When some start the molt the feathers fall out in clumps. These may be over the molt in a month or so. Some may take 4 months for all of their feathers to fall out. No matter how much you feed them these are not going to get over it any faster. With these you cannot tell by looking at them walking by that they are molting. Your best way to recognize it is to look for extra feathers flying around.
It will not hurt them to increase the protein if you want to. You probably have some still laying when others are molting so don't get too ridiculous about it. Everything in moderation.
Just for fun, I'll link last year's molting contest on this forum. That will show you how bad it can be.
https://www.backyardchickens.com/threads/official-byc-contest—post-your-best-worst-chicken-molt-pictures-2024.1641076/