My son has found a recipe to sick birds,
cooked egg yoke, 1 teaspoon codliver oil, very small drizzle of honey, 2 tbs natural yogurt, 2-4 tbs rolled oats, 1 desert spoon of beef cat food (not dog food for some reason) multi vit powder and 2 tbs grated apple, I have given the sickest one two very small meals of this mixture as she is an Ixworth and worth battling for, she is still not eating on her own but I have only just tried, also gave her a dose of anti biotics and will mix in some worming powder when I next feed her. it is now a wait and see.
the hens vary in age but mostly from last years hatching. I did make the mistake of buying in some hens that later turned out sick even though I had isolated them for a week, was told all flocks here in West Wales suffer from this bug, signs are difficulty breathing and sneezing though at the mo none of them are suffering from this, in future I will hatch my own replacements