I have a flock of about 40,2 started acting weird (stumbling, not eating or pooping) 2 days ago. Yesterday in cleaned the pen and saw a round worm in their stools, I immediately wormed with wazine 17 for the whole flock. Today 1 was up and walking around but had black tarry stools with slight blood. The othercchickens is now wheezing and railing as she breathes, struggling a little and yes her head and beak pointed to the sky. I plan on giving a dose of antibiotic tonight (oxytetracycline). Any ideas on what can be happening?! I've really been trying and I'm fearful death is the only way if not just 1 of them both