The Mistress and the Master were taking their wonted morning stroll through the grounds.

Lad cantered along, ahead of them.

The light bullet-scratch on his foreleg did not lame or annoy him.

He inspected everything of canine interest; sniffing expert inquiry at holes which might prove to be rabbit warrens; glaring in truculent threat up some tree which might or might not harbor an impudent squirrel; affecting to see objects of mysterious import in bush clumps; crouching in dramatic threat at a fat stag-beetle which scuttled across his path.
There are an immense number of worth-while details for a very young collie, in even the most casual morning walk; especially if his Mistress and his Master chance to be under his escort.

And Laddie neglected none of these things.