The photo above...that's IT! Now, this selection may change/grow as I gain more experience with fooling trout on "stocking day" around here....but for now, this will do it. The column of flies on the left side of the picture are simple patterns consisting of 3 feather fibers from a peacock sword for the tail, olive dubbing for the body, with brown or grizzly hackle palmered over it, and a small glass bead for a head. Not sure what the name of this pattern is. A kind gentleman at a trout stocking last year gave me one to try, and it worked AWESOME! Actually, first he gave me one without a bead, and it caught so many fish that the hackle was starting to unravel, so then he gave me the beadhead version. I sort of like the beadhead version better, it sank just a bit faster to get down to the trout sooner. Below is another picture of some of that pattern.
The second column of the top picture has some "experimental's" included in it, several of which use ginger-colored ostrich plumes for the body. Let's face it, we are targeting fish that are fresh from the hatchery. The only food they've known for most (or all) of their lives is manmade fish pellets. The ginger (tan, brown, or gray might also work) ostrich looks similar to a pellet, with just a bit of movement and a soft texture when the fish tastes it.
Something sort of similar to that, for those that would rather use/tie a pattern that looks like a trout's NATURAL food item (but could also pass for a pellet in a pinch) is to use some sort of scud pattern like those at the bottom of the 4th column of flies in the top picture, also shown below:
The third column of patterns in the top picture are microjigs. Now, technically the "microjig" pattern has rubber legs, but I rarely use them on my own microjigs. I've caught a LOT of fish, including trout, on them without legs. I prefer to use some color of grizzly marabou/chickabou for the tail. For the body of microjig, I like to use a sparkle chenille, with gold being my personal favorite. I've also done well with an olive mylar chenille. Other colors may also work well.
I've been told a Beadhead Prince Nymph under an indicator can work well for these stocked trout. I haven't tested that yet. If using an indicator, it would seem that a pattern that has more inherent movement to it would work better...like maybe something using rabbit fur, marabou, or soft hackle.