I had 100 but lost a few etc. Moveable hen house with tractor is essential. Electric fence with plenty of grazing (mine isnt switched on here every system is taken up). I have no idea of area its all visual but I am sure someone can confirm this. (We use 2 standard electric fences)
WE made our own off a trailer chassis, slated floor, timber built with recycled tin sheets. You can buy them on skids but you could be talking a lot of money. Do not bother keeping hens in one area it will be a mess. Plus worms, mud endless really. Hens need fresh pasture they need the bugs and its far healthier. In the depths of wet, windy and dark winters you need to bring them inside - we have a huge cow shed so they have the run of the place and eggmobile inside. Lighting to keep them laying in short light days.
Manual in and out personally too much hassle and risk with auto. You can get the odd hens hiding or trapped. No hardship getting out in the morning.
Yes its worth it as long as you market yourself well, have a USP, organic cert, good labelling, deliver. Do not under estimate your costs - 1t of food around £450 (direct from hipeak) seaweed meal, grit, oystershell, vets fees, mycoplasma, wild bird diseases, worming, vermin, birds of prey. You need to think around £2 for 6.
How you going to sell is essential to know. Forget basic restaurants only quality foodie establishments (need to get stamped etc) farmers markets are saturated with eggs and at £20 a table not cost effective. Anything that involves paying to sell isnt worth it working out margins is paramount. I worked out it costs £1.20 for a box.
Hybrids need changing every 12 - 18 months so need to find market to get rid.
Hope this helps. Its a good business as long as you can market yourself well, deliver and keep control of costs.