There actually used to be a hunger system in the dev version i believe, but its been temporarily removed for now. I think they've also hinted at adding a system to see certain cats from other clans too, but i'm not 100%
By messing a bit with files you can have it on (tbh I tried and it worked fairly easily ! )
the prey system is being worked on right now, you can turn it on but its not competely fuctional right now and we dont recommend it ! <3