Hello! I am new to chickens too! The best tips I have gotten so far are:
1. Put ACV (with the mother, it'll say "with the mother" on the bottle) in their water
2. Feed them plain yogurt (or hard boiled eggs, or both)
Those will help with "pasty bum" which is when poop covers their vent. If that happens get a warm rag and gently wipe it off.
3. Medicated Chicken Feed
4. Treats in moderation esp, meal worms, which apparently too many will cause dark poo and shut down their kidneys from too much protein.
5. Always feed grit with treats (I feed mine in a seperate container, they will eat as much or as little as they need) buy the chick grit as it is smaller (grit does NOT need to be fed with yogurt and hard boiled eggs)
6. Have blue lotion (or blue cote) on hand for any injuries.
1. Deep Litter method in the coop. Uses at least 6" of pine shavings and ag lime (or DE or Stall Dry) mixed in with it, and you never need to change the litter. Stir it around, add new litter and lime as needed. DO NOT use hydrated lime, as it will hurt the chickens!
2. Don't wash the eggs! It has "bloom" on them and it will keep the eggs fresh!
3. At least 4 sq ft per standard chicken in the coop, that is the "industry standard" so more space is good. But, if you live somewhere cold, you don't want it to be too big because chickens don't have body heat.
Hope this helps, and sorry if you already knew it!