I really like this one. Again, there's really no reason provided for the girl decision not to just swap back clothes in the evening after the training. Even more so after the first day since she know about it. Or to even continue after being wiped. But the change of settings is neat. There's the sense the other girls don't like her so it explains why they don't help, and the final trick is somewhat believable.
Oh, and I love the final visual of her being chained and seeing them leave, suddenly realising what's going on, trying to call for help and explain, but of course not being believed and whipped like the livestock she appears to be. All while the original livestock girl taunt her with a V sign. Very neat!