First of all, welcome to BYC!

There is a wealth of knowledge here, and I'm glad you joined us.
Next, it sounds like your off to a great start. Food, water, and a heat lamp is good, but don't forget the shavings/wood pellets on the bottom of whatever your keeping them in. If its just slippery plastic/wood they're on, they could develop splay leg (where their legs twist in their sockets as they grow.).
And that should keep them until they grow bigger, and you'll find yourself needing a coop for them to live in. For my ducks, I employ a kiddie pool. For chickens, water buckets.
Normally I don't keep ducks and chickens together in a confined space - but it has been done.
As your poultry grow older, day trips outside are nice in a little pen with bringing them in at night. And as far as I can remember, thats pretty much it.
And what are you feeding them?
Bird lice is just lice that lives on birds. I'm no expert on the different types of lice, but I know when my birds get lice, the lice do not suck on me. They stay on the birds, thus, bird lice.
I hope I answered all your questions, and if you have anymore feel free to PM me or post in another section of the forum!
Here is raising baby chicks:
https://www.backyardchickens.com/f/11/raising-baby-chicks
Have a great day!