Sounds like it may be your device processor performance. There is no known bugs for running Farm 2 on iPhone 7 and my game is working fine. The last update contained lots of new items so your device may be affected. Avoid running other apps in the background and try doing some housekeeping like clearing cache, restarting your device, switch off and on your connections etc if you have not done so. See more suggestions under Device Performance section. Our mobile is no longer just a simple phone these days, it's a phone cum camera cum notepad cum phone album cum music and video player etc... with everything together just eats up resources and processing power.