I dont believe that it's Favus on the comb because Favus spreads quickly and is contagious to other birds. Favus also appears "caked-like." However it wouldnt hurt to put miconazole on it if it were some type of fungus, wear disposable gloves when applying it.
As for the cracked beak, I've dealt with it before. Use a q-tip to gently dab betadine on the crack. It'll help prevent infection. Dont try to remove dried blood, you dont want her bleeding again.
Then leave the beak alone, another one will grow under it in time.
As far as eating layer feed, she might not be able to pick up feed with her beak in order to eat. She could starve if she doesnt eat. Also, pecking at food would be painful and she wont eat for that reason as well.
Provide a deep bowl for her to eat out of. Put layer feed in it and add water to make a watery mash. Keep it kind of watery throughout the day for ease of eating. You dont want her trying to eat (pecking) off a hard surface which could further damage the beak. Change the watery feed gruel each day and make it fresh for her to eat.
You'll have to separate her in a cage for quite awhile before she is able to peck feed from a hard surface. I had to cage my hen with a similar crack for almost one month. She was fine afterwards and returned her to the pen.
At about 3 weeks, put a few feed crumbles on a hard surface. If she is able to pick ALL of them up and eat them without dropping them or miss pecking at them, she can be returned to the flock. Ensure she is 100% able to eat normally, I cant emphasize that enough. Good luck.
I'm still learning ...
