Good idea that sounds like a real treat! Not many stores sell royal jelly by me, so I use baby food. So many flavors to satisfy any roach species!I give mine royal jelly in honey and they love it. It is a sweet treat for them.
I have used it to help injured or sick roaches get back on their feet. I think it actually works to help them heal and keep their energy level up. I have 3 roaches that would have probably died from their facial injuries if I didn't feed them that, they were chewed on by other roaches during their molting..