You can nominate one master list to push contacts to (from Sheep into Mailchimp). When a contact changes in Sheep it is re-sync's to Mailchimp every few hours. The following fields are pushed to Mailchimp and can be used to build segments for use with your Mailchimp campaigns.

first name
last name
email
tags
locality
language
connected organisation
groups & group role
active memberships

Please note that Mailchimp has its own delays. Although the data may have been pushed to Sheep it may not show up in the list preview or on the individual record. However when sending a campaign Mailchimp does appear to always use the latest data.

Sending a static segment to Mailchimp

If you have a static set of contacts selected from the directory you can push these to Mailchimp using the Actions button.

Navigate to the directory
Open the filter panel and choose the filters that you need
Click "Apply Filters" and close the filter panel
Quickly check that you have the intended results
Select "Actions" and choose "Create Mailchimp Segment"
Pick the GDPR legal basis and provide a comment for audit log
Name your segment
Click "Create" (your filter will now be queued and sent to Mailchimp)

Notes:

Mailchimp changed the way to manage static segments in 2019. Static segments are now listed as 'tags'. You will find your new static segment or 'tag' listed as SheepCRM export with a date stamp (unless you provided your own name).
Contacts must already be in Mailchimp. If your SheepCRM filter has contacts that are not in MailChimp then the segment in Mailchimp will be smaller than the Sheep report.

Using your Segment in a Campaign

The purpose of creating a segment is almost certainly so that you can send them an email.

Mailchimp document this process but this is a quick summary:

Create a New Campaign
Choose the Audience
In the Segment dropdown pick the Segment you just created (note it will have a Sheep prefix and will take a few minutes to sync across)
Continue to design and send your campaign

Note: If you need to send to multiple segments then choose "Group or New segment" in step 3. When prompted choose a rule based on tags matching the segment names. (Note Mailchimp now call segments tags - see below)

Mailchimp naming, segments, segments and tags

The confusion is the Mailchimp naming:

"dynamic segments" - these show as "segments" in Mailchimp

"static segments" - these show as "tags" in Mailchimp

A "dynamic segment" is a segment based on rules "dynamic" implies that the segment will change with the data. An email joins or leaves the segment through a change in data which the rules observed.

A "static segment" conversely does not change. An email joins or leaves by being directly added or removed from the segment.

A tag applied to a contact in Sheep will be sync's to Mailchimp and appear in the tag list.

A "Sheep segment" when sync'd to Mailchimp appears as a "static segment" (that is it appears under "tags" because it is "static". A client may have hundreds of tags so to help distinguish Sheep segments all begin "sheepCRM segment: " e.g. sheepCRM segment: member news