The slime egg is basically abandoned. The original
author bio longer has time to maintain it and is no longer
writing chicken code. I put in some patches to prop it back up
to a point it would execute, but...
(Shameless plugs inbound). There's also alpha-quality
support for chicken in development for geiser, as well as the
chicken-scheme.el package.
Chicken itself ships with chicken.el, as well.
https://github.com/dleslie/chicken-scheme.el
https://github.com/dleslie/geiser
I would appreciate feedback for geiser, of you're
interested.