Rails vendor assets not serving .. no route found error

I am working with ruby 2.2 and rails 4.2.

In my application there are many CSS and JS files that I want to load from the server only when needed.But when whenever I am calling the stylesheet from independent folders in vendor using stylesheet link tag I am getting no route match error

ActionController::RoutingError (No route matches [GET] "/vendor/theme/assets/stylesheets/application.css"):

I have tried adding the routes to "Rails.application.config.assets.paths" but still not working.

I tried using public folder for the same purpose but still not working.

Is it possible to server these assets without precompiling them as only some individual pages require these assets.Kindly suggest.