Because you are using activated procedures service broker will shut the queues down if the activated procedures do not process messages. You can use ALTER QUEUE to set the activation status to off then let the messages build up, then turn the activation status back to on when you are ready to process again.

Configuring service broker for using local and remote services the service broker routes the messages to can be complicated and it not very easy when you want to reconfigure.

If it were me, I would avoid the activated procedures and build a separate service (process) that can reside anywhere (or multiple places) that reads the queue(s). Much easier to reconfigure and less sensitive to server load.