Let's assume that KFC had some logic behind this, such as if only the grilled chicken purchases went to the fundraising effort, then the total amount raised would be less. So they added the fried chicken too. I would suggest a sale price on the grilled chicken ALONG WITH the donation, encouraging customers to try the healthier alternative. The sale price would be some percentage of what was expected to be raised by the fried chicken bucket. Thus they give two incentives to encourage healthier eating.