Chipotle Mexican Grill’s stock took a big hit from investors worried that years of fast growth are over. The culprit? A one-two punch of slowing growth and high food costs caused by this summer’s drought. Chipotle said third-quarter revenue and net income both grew, but slower than last year. The chain also missed estimates. Another concern was a weakening sales forecast. Chipotle predicted revenue growth in stores open at least a year would be flat to up in the low-single-digits next year. That is down from this year, when it expects it to be up in the midsingle-digits, and lower than last year’s gain.