Not going on daylight savings time does not change the actual hours of daylight that your birds are exposed to, but decreasing day length without supplemental light could certainly be a factor. The problem could be a combination of the new feed and change in day length. These two stressors done at the same time could certainly be a cause for reduced egg production. You can start supplying extra light to make sure that your birds have 16 hours light and 8 hours dark, but the ones that have quit laying may not start up again until spring, even with supplemental light. I will comment that two dozen eggs from 150 chickens is a rather low rate of lay to begin with. You don’t specify if all of them are of laying age, but if they are, you may want to reassess your feeding/management program if egg production is a priority.
Is the new feed you are feeding a complete feed and if so, is it formulated for layers? If your new feed is not a true complete feed, your hens could be missing out on some essential amino acids, vitamins and trace minerals that they were receiving with the previous diet. Another thing to consider is the protein source. Soybean meal has the best amino acid profile of all the plant proteins. Since your new feed does not use soybean meal, the amino acid profile may not be as optimal as needed to support a high level of egg production. Additionally, evaluate the physical form of your feed. If your new feed is a mash, as many organic products are, it could be that some ingredients are settling to the bottom of the bag or feeder, so your birds may not be getting a nutritionally complete meal, even if the feed is formulated to be complete. Mash products often are not eaten as well as crumbles or pellets simply because the bird has to work harder at it. Your birds may be eating less feed than previously and doing more foraging, which would reduce the amounts of critical nutrients they are receiving.