Seniors have a special menu prices. Base on my experience for birthdays it depends on the local management
If you sign up, the send you a birthday gift..via email,present coupon with ID you get a free meal (whatever they decide in email info)
Not seniors. Birthday folks get a free grand slam which is 4 items from grand slam menu. You still pay for your drinks. Drinks not included. That's sucks. Not really a free birthday meal. Meals come with a drink... Usually.
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