Linux removing folders older than 1 year and more than 3 files

ANT selectors enable you to customize the fileset to delete.

Try the following:

<target name="purge">

    <tstamp>
        <format property="touch.time" pattern="MM/dd/yyyy hh:mm aa" offset="-300" unit="day"/>
    </tstamp>

    <delete>
        <fileset dir="${src.dir}">
            <date datetime="${touch.time}" when="before"/>

            <scriptselector language="javascript"><![CDATA[
                if (file.getParentFile().list().length > 3) {
                    self.setSelected(true);
                }
                else {
                    self.setSelected(false);
                }
            ]]> </scriptselector>
        </fileset>
    </delete>
</target>