Some sound advice from poultry breeder, columnist and author, Andy Cawthray.
Prior to picking up your chickens make sure their new house is ready and any fencing is secure. Put the feed and water in the house (the water indoors is only temporary, drinkers are always best kept out of the living quarters) and check the ventilation on the house is open.
Before you head out to collect your chickens check with the seller has carry boxes available, if not then you will need either a sturdy cardboard box (with air holes) or a pet transporter of an appropriate size. Food and water is not essential for the occupants unless the journey is going to be particularly long. If you are collecting during the warmer months then try and make the collection time as late as possible in the day so as to avoid any high temperatures.
When you get the chickens home place each bird into the coop giving them but don’t let them out into the run, leave them indoors where the food and water is so they can settle into their coop. They will roost in their overnight and hopefully when you let them out into the run the following morning they will realise the coop is where they roost. After a couple of days the birds will have got their bearings and will be happily wandering in and out of the house. The drinker can then be placed outdoors, along with the feeder if you intend to have it positioned outside.