I notice in this post people are unsure what brooding means. Basically it's the period between when a chick hatches and when it's old enough to fend for itself. Usually this is up to 8 to 10 weeks or so. If the hatch was being brooded by a mother hen (broody) then she would protect and keep the chicks warm by sitting on them or sheltering them under her wing. She would lead them on forays to find food (foraging) and would feed them by dropping food in front of them so they learnt. She would also protect them and introduce them to the flock. If you artificially incubate you will have to use a method of husbandry to replace a broody's attention. This basically means a secure housing which provides heat and food untill they are able to find food and feed themselves and are fully feathered (fledged). Some of the heat sources which are used are known as brooders but they are just part of the husbandry requirements you will need.
Below a Spangled Orloff hen extends a protective wing over a member of her brood while a Welsummer and Cream Legbar look on. In this case a L/F Vorwerk chick who is getting a bit too big for mum!
Traditionally heat lamps are used for most brooders where you have 6 plus birds. A high walled enclosure (400 to 600 mm is OK and this can be covered with a net to stop them flying out as they get older) preferably round so there are no corners to trap the chicks should they cram together. I use an octagon I made from old wardrobe doors which I cover with rigid plastic netting the sort you can use as edging around flower beds. I make 3 panels by weaving a garden cane into a 1.5 metre or so length of it and use these to cover the octagon from around 3 weeks age when they start to become more flighty.
The enclosure should not be fully enclosed but ventillated at the top. Make sure the heat source heats a hot spot of around 37deg C initially with a temperature gradient towards the outside. They need to be able to move away from the heat source if they get too hot. If they are always huddled directly under it, it's too cold, or always round the outside, it's too hot. Aim for a even distribution around the source. They will find the temperature which suits them by moving in or out. Raise the heat source gradually so they can be off heat by 5 weeks. Towards the end turn off the heat source during the day and just have on at night if in an outhouse, which is always best in my view.
Using purpose made chick feeders with chick crumbs ( I prefer medicated feed which guards against cocci) and drinkers I find better than improvising using dishes etc . These invariably become fouled with droppings or wet the chicks whereas purpose made ones are designed to minimise these problems. Raise them up as the birds get bigger to above vent height and discourage them from perching on them by having a lid or covered roof.
Provide the chicks with things to explore and play with so they stay active and don't develop bad habits like feather pecking. An old CD suspected on a string or a perch or boxes to clamber on are all appreciated. Keep the litter clean and provide clean water daily and blow any shavings off their feed and keep free of droppings. Watch the birds for balls of droppings forming round their claws or their vents and gently remove using water to soften it first.
HF