Leya and Jessie don't care much for the men they own. They are slaves and regularly treated as such. That's why even though this slave has worked well for the girls this week, it really doesn't matter and thus they will heavily degrade him. They have been walking barefoot outside and need the slave to lick their filthy feet clean, so may as well have him eat leaves while he is down there worshipping. It's just another humorous way for Leya and Jessie to degrade this male foot licking pet.