DD's bedroom window has a clear view down into next-door's kitchen.
At bedtime DD drew my attention to several mice who were bolting out of the kitchen skirting, feasting on crumbs and generally having a high old time while neighbour (who is very nice, tho' not a bosom pal) was safely away upstairs giving her many children baths and putting them to bed.
What's the etiquette here? Would you want to know? (I would, I think.)
surprised your neighbour hasn't noticed if her kitchen is infested
If you want to be kind say something along the lines of "Hey neighbour, I've had a few mice droppings in my kitchen, perhaps you want to have a look at your kitchen/house just to be on the safe side - no biggie"
Up to you, although I'd love to watch those mice having a high old time