S.W.
You should complain about them closing without calling you, but yes it is legal. Ask for a discount on your surgeries, as well as make sure that you aren't charged another day of boarding! I worked for vets when I was younger and they ALWAYS have someone go in and feed, water, walk, medicate etc.. even when the office is closed (like Holidays and such- and no they don't answer the phones). I always had to work Thanksgiving and X-mas. Hope this helps.