Turns out Pfizer is having problems getting an ingredient they need to produce it. You can do a search and there's still some places that have some. I just discovered this today when I got a new kitten with an eye infection.
The key is keeping them cool - we use a mister and ours are quite happy. But then - those are adult chickens too. baby chicks do just fine with a fan. In fact once it's dark we put a small lamp on ours. One of those little round silver clip ons you see in most workshops with a 40 watt bulb will...
Got my first chickens a little over a week ago - one adult americauna, a buff orpington pullet, two americauna chicks, and a buff orpington chick. Went back and got 4 more americauna chicks. Thinkin about starting a small chicken farm (I have an acre and nothing much to do with it).