Surveyors know what crowsfeet are and when to use them. I created a 12min. video that shows you how to make a dynamic block that allows you to position the crows feet symbol at the endpoints of a line using grips.

I show you step by step how you can edit a block and add a Polar Stretch action that forces the arrows to stay aligned with the line. The same behavior can be adapted for labels that use text and/or other symbols. The secret is chaining several actions to the same Polar parameter.