Explore Lulukoko, Tsukuyusa, and Westown in this multi-cultural farming game for Nintendo 3DS. [ Game Guide ] JP release = Jun 2016. NA release = Feb 2017. EU release = Oct 2017.
there's no bell but you can get pets that herd. just check their skill before you buy and if none of them have the herding skill, press b to go back to the original option and then select buy animals again and the pets will have different skills
There actually is a bell you can buy that you upgrade much like your other tools. I'm assuming that the more it's upgraded, the more animals it will herd when you ring it. (It is a hand bell)
I've never bothered to upgrade mine because I have animal herding pets and I've never had an animal get stressed out from never going outside. So generally, they stay in the barn.