Soft-hackled Frenchies rule. They catch plenty of trout, both new stockies and grizzled veterans.
Sometimes, trout want a very simple fly with few details, as it means there’s less to which they can object. Sometimes, “busy” flies with many strike triggers work.
A soft-hackled Frenchie offers many triggers: segmentation, a tail, seductive movement via the soft hackle, multiple color contrasts, a bit of shine, and an enlarged thorax. Some really huge fish, both stocked and wild, have fallen for this fly.
I tie them on jig hooks, and they’ve been great anchor flies for Euro-nymphing in faster water. It’s a Pheasant Tail variant with a few twists.
Here’s what I am using these days:
Weight: 0.015 non-lead wire and a slotted tungsten bead
Tail: light Coq de Leon
Body: pheasant tail
Rib: gold wire
Thorax: ice dub
Soft hackle: partridge or Brahma hen
Hot spot: orange thread color
Pairing this busy fly with a very small and plain-looking fly when nymphing is often a good call, IMO. You give the trout a choice and thereby can see what they prefer on that day or hour.