I'm sorry, but I would always target-feed filter feeding animals regularly to
ensure they are getting enough food
.
"I've had mine for months now and they are thriving" - thats great and hopefully this means they will have grown noticeably by now and the females are producing masses of eggs, but you cant assume your tank is the same as everyone else's
. Your tank obviously has enough free-floating organic waste to sustain several large shrimp, but in more strongly filtered tanks or newer tanks, they would starve.
These shrimp can simply take months to slowly die, getting very slightly smaller with each shed in tanks that have a little food but not enough for them to grow and breed, so it's not always easy to tell if they are thriving.
Buying a specialist feeder like filter shrimp and not target feeding is risky for the shrimp IMO. Having kept these in different types of set-ups over the years (shrimp only, and heavily stocked with fish), I would always rather be sure they are eating than have them go hungry and not realise until they die from a bad moult - at least partly due to bad nutrition. The only time mine ever thrived (rapid growth+eggs) was when I target fed, though they appeared perfectly fine in the other tanks - until they suddenly died months later.
Just my experience
.