They had come to fire the house, their visit expected because they had been before. On that occasion they had come later, in the early morning, just after one. The sheepdogs had seen them off, but within a week the dogs lay poisoned in the yard and Captain Gault knew that the intruders would be back. ‘We’re stretched at the barracks, sir,’ Sergeant Talty had said when he came out from Enniseala. ‘Oh, stretched shocking, Captain.’ Lahardane wasn’t the only house under threat; every week somewhere went up, no matter how the constabulary were spread. ‘Please God, there'll be an end to it,’ Sergeant Talty said, and went away. Martial law prevailed, since the country was in a state of unrest, one that amounted to war. No action was taken about the poisoning of the dogs.
Does the first sentence in bold mean: we have lack of soldiers? or We are so busy at barracks?
and so "stretched shocking" mean: being busy is really shocking? or lack of soldiers is really shocking?
Source: The Story Of Lucy Gualt by William Trevor.