I have two I-Pads I play on. I touch the farm hereo icon , it goes to the game and when I push play it goes back to my homepage. I have been playing on both pads for a while

Two things possible here: Either you've got another app in background hogging available RAM or the App itself is faulty.

To check first option: Reboot your ipad and try the game first thing after that. If it works you had too little free ram for it to start.

If that doesn't fix the situation: Uninstall and reinstall the app. Push and hold the App-Icon until all icons start to wiggle. Your App-Icon now has a badge with an X in it. Klick that to remove the app. To stop this wiggle-mode press the home button once.

Then go to App-Store and re-install the app.