we have 4 hens, none of which have layed. they are about 5.5 months old. one clearly seems to be ahead of the others (much redder comb and waddle). yesterday she started acting funny (she's a barred rock). she started moving really slow (walking and when she tries to run), hanging out by herself and she has trouble maintaining her balance. we thought for sure we would find an egg this morning, but nothing and she's still behaving this way. she is still eating. any ideas? is this normal?