Funny you mention it. My brook trout are doing the same. I wanted to feed them 2 X per day all summer and just didn't get much of a response. Now they are feeding 2 X per day. Water temps are the same as summer.

What species do you have? Are they fall spawning rainbows or browns? I notice some species feed heavily preceding their spawning period. This may be an adaptation of natural selection to handling the stress of spawning, when not as much feeding takes place, and of course a lof of energy is going into gonadal development.

Not sure about "getting ready for winter" but it could also be an adaptation of natural selection to store up fat reserves.

One thing you may want to consider. Your fish may be closer to the surface and to the feed now, with lower light levels. Has the water temp cooled any? Lower water temps more in their optimum metabolic range can definitely be a factor.

My brook trout are so light shy that within a half hour of sunrise they will not come up for feed. If I catch any during the day they will be down around the bottom in 7 to 9 feet of water. I never ever see them cruising the pond. However, I have a strain of brook trout that have not been very domesticated so that may be a factor. They are so shy they grab the feed and dive immediately.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.