Hens are not the most aerodynamic of birds! Heavy breeds such as Marans and Orpingtons seldom attempt flight but some lighter breeds are more adventurous. A determined hen can fly for a short distance if she sees an inviting foraging area over a fence.
Hens commonly fly down from high perches and some enjoy roosting in trees. Hens will fly to escape a predator but also when they see you approaching with a feed bucket or titbit they will excitedly rush towards you and often take off in the process. Under normal conditions hens have no desire to fly out of your garden and if given sufficient enrichment in their environment they will not be constantly looking for greener grass next door.
Anatomically there is no reason why hens shouldn’t fly. Nature has provided them with strong, lightweight pneumatic bones which are specially adapted. Vertebrae near the wings are fused to provide extra strength and the tail acts as a rudder during flight.
One essential requirement for flight is feathering. Without wing feathers birds cannot achieve flight. For this reason trimming the flight feathers on a hen’s wing essentially grounds it.
It is only necessary to clip the feathers on one wing as this unbalances the hen.
How to trim wing feathers
You will need a large sharp pair of scissors
Ideally one person to hold the hen while a second holds and trims the wing
Extend the wing fully
Imagine your own arm. The part between your finger tips and elbow has the long primary feathers with a shorter fringe of covert feathers overlapping. The part from elbow to shoulder has the secondary feathers.
Carefully cut in a straight line just below the point where the primary (long) flight feathers meet the covert (shorter) feathering taking great care to avoid cutting the body of the wing itself.
ONLY the primary feathers should be cut. You should expect to cut between 8 and 10 feathers (Normally 10 but some feathering may have been moulted). If the hen can still fly it may be necessary to cut the secondary feathers as well.
Once the wing is folded back into a natural position against the hen’s body it is not noticeable that the wing has been cut. If you slightly lift the covert feathers as you trim the primary feathers they will disguise the cut edge of the feathering.
Growing feathers will contain blood (the quill will be dark) Do not cut these. Only trim if the quills are white.
This video shows how to trim a wing https://www.youtube.com/watch?v=750NtdtUgWI&feature=youtu.be