i got 15 chicks in the mail one died right away there are more then a few now that are listless. there eyes are not bright and they kind of shut there eyes and have touble breathing there beaks open gasp for air a few times then shut there eye and slowly lower to the ground. i noticed when they gasp that there is a yellow? mucus there. what is wrong i noticed more then a few have it. they do eat and drinkish. help please.