No it's not, because if food stamps/etc were unavailable, employees would be willing to work for less.

Since we have a minimum wage, McDonald's can't legally get labor any cheaper than they currently do, no matter how much the labor supply increases.

McD's currently has an average hourly wage of $9.01, well above minimum wage.

http://money.cnn.com/2015/04/01/news/companies/mcdonalds-pay...

Only 1% of the country (4.3% of hourly workers) earn minimum wage or below. So your argument is almost completely irrelevant.

http://www.bls.gov/opub/reports/minimum-wage/archive/minimum...