The BotBuilder SDK rc build feed is found on TestPyPI.
The daily builds will be available soon through the mentioned feed as well.
You can tell pip to download packages from TestPyPI instead of PyPI by specifying the --index-url flag (in the example below, replace 'botbuilder-core' for the name of the library you want to install)
$ pip install --index-url https://test.pypi.org/simple/ botbuilder-core
If you want to allow pip to also pull other packages from PyPI you can specify --extra-index-url to point to PyPI. This is useful when the package you’re testing has dependencies:
pip install --index-url https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple/ botbuilder-core