I have a walk-in simple wire enclosed cage apx 5 feet in diameter and 6ft high.
I keep 14 canaries even during the winter in the outside cage and feed only canary seed and plenty of greens. The greens are the important part of the diet.
There is a water bath as well as drinking water for the birds. When it freezes the water has to be thawed or hot water put in the drinking bowl.
In March I offer plastic empty nests and an assortment of strings and grasses for the hens to build their nests.
I do not have any health problems and the birds care for their own young. In August I give the baby birds away and that is all the care I offer.