In order to maintain her place in the pecking order, a hen will disguise the fact that she is not feeling well. Handling on a regular basis is very important as it is the only way to tell if a bird has lost weight or not - even when really thin their feathers disguise this fact, so handling will give a vital early clue to any problems. Not only loss of weight but excess weight can be assessed by feeling the flexible pin bones either side of the vent (cloaca): they feel sharp if the bird has little fat and well padded if too fat. The distance between them will indicate if the hen is laying: three vertical finger widths between the bones indicates production and less than two, the reverse.
The welfare of the birds has top priority so handle them gently but supportively. Hold the bird so that it is balanced by resting its weight on your left forearm, its head under your left arm, its legs held between the fingers of your left hand with its tail pointed away from you - the ‘dangerous’ end, particularly with waterfowl! A balanced, well-supported bird will not struggle. This leaves your right hand free to inspect the bird for positive signs of health, or lice or mites.
If you first come across a hen in a cardboard box, slide your outstretched hand, palm up and fingers spread, blindly into the top of the box, then under her once located, her breast should rest on your outstretched palm, her legs between your first/second and third/fourth fingers. Your other hand is placed over her back to balance her as you lift her out of the box. Take the weight on your forearm and hold her close to your body, her head pointing towards your armpit, leaving your other hand free to inspect the bird. Be firm but don't squeeze the body tightly as this may temporarily harm the breathing mechanism. This principle of holding applies to all species and all sizes of poultry - the bird is balanced and comfortable and the mucky end is away from you. The hip of any poultry will dislocate with horrifying ease if a bird is held by one leg. Do not hold them by the legs upside down.
If your first introduction to a hen is not in the confines of a box or crate, begin by practising in the dark with a very dim torch when the hens should be on their perch. If you move quietly and slowly, talking to them all the time, you will not startle them and you can then pick one hen off the perch with both hands around her wings and body, facing towards you. Then continue by sliding one hand under her as above.
You are likely to need to catch a hen during daylight hours, so obtain a fishing landing net as this can (with practice and the aid of a fence or wall) be dropped over the hen and you can then pick her up as above. This is much less stressful for both you and the hen than chasing her around the pen or garden as she will be able to run and jink much faster than you.
Hens can become really tame if handled correctly on a regular basis.