Found this on my chicken this morning? Any ideas what it is?

I went to feed my chickens this morning and noticed that this chicken did not want to come out to eat, she still drinking water and looks overall fine walking around and everything but I noticed this little cyst in front of one of her eyes everything else looks normal though, I drained it and some clear liquid came out. Has anyone seen this before, should I be worried it could spread to my other chickens?