I'd imagine that they would eat the shrimp. What I would be more concerned about is how fast they are eating the shrimp. If the shrimp are relatively established they might be able to keep up with the predation from the gars. Myself I'd probably try it. Pick some up, put them in their own tank and add the babies to the main tank as they hatch out.
One of my buddies had breeding populations of cherry shrimp in his tank as well as a synbranchus eel species. Even with this larger predator there were still plenty of shimp.