1. Eggs
  2. Introduction
  3. Installing eggs
  4. Loading eggs
    1. In CHICKEN 5
    2. In CHICKEN 4
  5. Keeping eggs in an alternative directory
  6. Source code
  7. Contribute


Eggs are CHICKEN-specific extension libraries, conveniently packaged in a source archive. They are stored in a centralized repository and can be downloaded and installed (mostly) automatically. You can also create a local mirror of the repository, if you prefer.

The egg index is the official list of eggs for the latest CHICKEN major version (5), along with their documentation. If you are looking for eggs for the previous CHICKEN major version (4), they are here For software archeology and legacy systems CHICKEN 3 eggs are kept here.

You can subscribe to the egg RSS 2.0 feed for CHICKEN 5 or that for the legacy CHICKEN 4.

Installing eggs

To install any of the eggs, run the following command, replacing name for the egg's name:

chicken-install name

This will download the egg and install it. Enter

chicken-install -help

for a list of options or consult the chicken-install(1) manual page.

Loading eggs

To load and import an egg into your program, use:


(import egg-name)


 (require-extension egg-name)      ; load library code, import identifiers

To restrict, rename, or prefix imported identifiers, you can split up the load and import pieces:

 (require-library gopher)          ; load library code

 (import (prefix gopher gopher:))  ; import identifiers with a prefix

Keeping eggs in an alternative directory

Note: this is for CHICKEN 4. You can keep the eggs repository in a different repository. See the Extensions/Changing repository location section of the manual for more information on that.

Source code

See How to obtain the source code of eggs for more information.


If you want to help document the eggs, please consult the Documentation section at the eggs tutorial page.

If you want to contribute new eggs, you might want to consult the eggs tutorial and the official, automatically built, list of eggs: egg index.

In case you don't have a Subversion account, check the Contribute page to know how to request one.