Familiarity is the main argument for the own cage
A bird's cage is its territory in a way few other pets match. It knows where each perch sits, how high the food cups are, which corner it sleeps in, and which toy it leans against. Moving that whole world intact into a boarding room removes one entire layer of novelty: the sounds and people are new, but home itself has travelled with the bird. For nervous species, older birds, and birds that have taken a long time to accept a new perch or cup at home, that continuity often decides whether they eat and rest normally from the first evening.
An own cage also removes cage-sharing questions. There is no previous occupant, no doubt about cleaning between birds, and no unfamiliar bar spacing or door latch for your bird to test.
When the boarder's cage makes practical sense
Very large cages for big parrots may not fit through doors or into a car without dismantling, and a cage taken apart and rebuilt in a strange room loses much of its familiarity advantage while adding transport risk. A boarder's cage can also be the better choice if your home cage is due for replacement, is difficult to clean thoroughly before the stay, or is an aviary-style setup that simply cannot move. Good boarders keep appropriately sized cages for the species they take, position them away from direct contact with other birds, and clean them thoroughly between guests.
If you accept the boarder's cage, visit and inspect it: bar spacing suitable for your bird's size, secure latches, no rust or flaking coating, and enough room for a full wing stretch and movement between perches.
Bridge the gap if your bird uses their cage
You can soften a cage change by sending the contents of home with the bird. A familiar perch at the right height, the usual food cups if they fit, a favourite toy, and the sleep cover your bird knows all carry scent, texture, and routine into the new frame. Ask the boarder to set the cage up in the same broad arrangement, food and water in similar positions, sleep corner away from the room's busiest side, and to give your bird a quiet first evening before expecting normal interaction.
Bring your bird for a short look at the boarding room beforehand if the boarder allows it, so the first stay is not also the first sight of the place, the people, and the cage all at once.
Whichever cage, the routine must travel too
Cage choice only solves the physical side. Feeding times, cover time, handling preferences, and the words your bird understands still need to reach the people on duty, including staff your bird has not met at drop-off. Write the setup down as it applies to the cage actually being used, noting perch and cup positions if they differ from home, so nobody improvises.
If your bird refuses food, stays fluffed and silent, or injures itself against unfamiliar bars in a borrowed cage, the boarder should contact you and your vet promptly rather than waiting out the stay. A KinsLe Care Pass hands the boarder temporary, clear access to your bird's routine for whichever cage is used, so every member of staff works from the same setup you agreed.