My 4 production red have been pretty chill so far. Usually when I reach my hand in to grab their feed, they run the other way. Tonight, one tried to go after my hand, so I grabbed a pair of shears and gently pushed them away from the feed. Then all of them came over and tried to peck at the shears. Is this normal? They have been pretty calm until recently, they have began to display aggressive behavior. They are 5 weeks old.