Coryza is a form of CRD..
but one of the main symptoms is swollen wattles and head..
here is a link for info about CRD :
http://fowlfacts.proboards40.com/index.cgi?board=afflictiondiseaseff&action=display&thread=1185
Tylan 50 and Tylan 200...the difference is in the amount you give..since...
erythromycin is good..
but they may need some Tylan 200 or Tylan 50 injectible..
it's possible they could have a combination of problems..
they could also have cocci..
best thing to do is get a fecal float done at a vet..to check for worms and cocci..
sounds like they might have Coryza...