Opening website links (received via email messages) directly from email client like Thunderbird or Outlook in your default browser may involve a potential security risk.
If you can check the link destination before opening the link in your default browser might be good. For Thunderbird, you can integrate a mini browser in it with the add-on ThunderBrowse.
With ThunderBrowse you can check any link within your Thunderbird without opening your browser. Moreover it works faster than your default browser.
To install Thunderbrowse, download and save the file to your hard disk. In Mozilla Thunderbird, open Add-ons from the Tools menu. Click the Install button, and locate the file you downloaded and click “OK”.
After installation follow the simple setup wizard. Normally default settings are enough for security; however you can configure it from the add-on option menu (Tools – Add-on – ThunderBrowse – Option).