Note that the poaching email does not have any other contact details other than the leaver's - this is to try and funnel all enquiries to the leaver as part of the poaching plan! More tips here.
Dear [Customer name] Our store will be closed from [date] to [date] for Thanksgiving. We are assure you all of your emails will be answered once we are back on [date]. Kind regards, [Name/signature]

Yes, mine (for external e-mails) typically says somethingalong the lines of “I’m out of the office until [date/time] and messages to this address are not monitored in my absence. I will respond as soon as possible on my return. If your message is urgent, please re-send to my assistant [email address] or telephone [assistant’s number]” Internal it will usually just say “I’m out until [date/time] pass any urgent enquiries to [co-workers] ” although my assistant and a couple of others have my home number and personal e-mail so can get hold of me in a genuine emergency, and I will sometimes speak to them in advance if I’m willing to lower the bar on what amounts to an emergency, but I would not expect any of my employees to do that !
we had something similar at one phone-heavy place I used to work and it was actually extremely useful – everyone set their voicemail when they got in, and people would include if they were offsite (so worth ringing their mobile) or likely to be otherwise unreachable, and who to contact if your query was urgent. only took a minute to set, and was super useful to me as someone who had to talk to maybe 10-20 people on the phone in a day.