Not only do the dogs dine on excellent food, cooked by a world class chef, but they're also free to roam the Palace with impunity. Former Royal staff - especially those who've served as footmen or in servile roles - have gone on record to say that nobody is allowed to shout at, chastise or otherwise attempt to discipline the dogs, or else they'll face the wrath of the Queen herself.
Because the dogs aren't disciplined, they do as they please wherever they like. Some former staff have said they're not house-trained, and if they need the toilet they'll just go wherever they like; even if 'wherever they like' is against a priceless antique piece of furniture! Many Royal servants carry blotting paper at all times for this exact reason. That has to be one of the bigger downsides of working in the Palace.