I was listening to an interview with Courtney Humphries, the author of Superdove: How the Pigeon Took Manhattan ... And the World on the Scientific American podcast. The book is about pigeons, and part of the book concerns the amount of scientific research done on pigeons.
Pigeons have been the subject of several major biological research programs. Perhaps most famously, Charles Darwin talks at some length about pigeons and pigeon fanciers in On the Origin of Species. Fancy pigeons interested Darwin because they came in so many forms, yet were all descended from a common rock dove. If a few breeders with a few generations could cause such changes in form, imagine what Nature could do with vastly more time, Darwin argued.
Pigeons were also used in many key learning experiments by B.F. Skinner. Superdove talks about one of the stranger applications of this -- a proposed pigeon guided missile -- but the weirdness of that should not distract from how much they taught Skinner about learning mechanisms.
Then there's a branch of research about animal navigation, and clearly homing pigeons have contributed large amounts of knowledge there.
Yet despite these significant contributions, pigeons are not really considered a standard model organism in science today. Arguably, they could have been. But today, arguably the most prominent model organisms for animals are the fruit fly species Drosophila melanogaster, the mouse species Mus musculus, and the nematode worm species Caenorhabditis elegans. For plants, it's Arabiopsis thaliana.
Why did these win and pigeons not? The big four listed above were all model organisms for genetics. They were among the first to have a complete genome sequenced. And with the rise of molecular biology, that is a tremendous facilitator for research.
If Marmorkrebs have any hope of becoming a model organism for researchers, there needs to be a crayfish genome project.