BTW, let me take a broader view of this "art movement". I suppose the chicken masturbation is a stretch but not really. There is apparently an "art" movement which specifically Nadezhda Tolokonikhova was/is a member and that museum show and was/is (I do not know her exact affiliation) with the "art" group Voina whose antics include setting fire to a police car, the art museum orgy (Nadezhda was present as a member), the phallus on the drawbridge etc etc all similar vain and disconnected "art" and "political statements".
Not safe for work!
http://plucer.livejournal.com/266853.html (Voina "art" group)
http://plucer.livejournal.com/55710.html (Nadezhda is a member of the "performing art" group)
http://plucer.livejournal.com/281211.html (the chicken stunt)
So we are not talking some random, silly stunt. This is a group of determined individuals set to "perform" their "art" and anybody pretending they would have stopped if given a stern talking to is just deluded. A punishment has to have some deterrent value also and these silly girls have performed such "art" on many an occasion. This simply is not a simple, unintentional act.