First few days: just like any other chicks (for heat, shelter, etc.) So think of what you would do for egg layer-type chicks, and make sure it is big enough for 50 of them.
How soon they are off heat will mostly depend on the temperature in your area. Because of how fast they grow, they can often be off heat before they are fully feathered.
If you give them a great big space, with heat near one corner, you can watch their behavior: chicks that sleep away from the heat are chicks that no longer need heat. That works for pretty much all chicks, in all climates.
Most tractors are designed to provide enough shelter, except that the chicks might need more at the very beginning. For extra shelter at first, it sometimes works to use tarps, or pieces of cardboard, or empty feed bags, or anything else that can be attached to the tractor and block wind & rain for a few days or weeks.
Very young chicks might have trouble if you move the tractor onto fresh ground that is wet or cold. As they get older, that becomes less of an issue, and of course it depends on what your weather is at which point: just-shipped chicks are much more fragile than month-old chicks. You might consider keeping the tractor in one place for at least the first few days, while the chicks recover from shipping and learn how to eat, drink, get warm, etc.
If you butcher them at 8-10 weeks, they are still basically babies, and act like most other chicks of that age except for being obese and having enormous appetites.