"You are a canary, so you should keep it in a cage." What does this sentence mean?

This sentence means that you can't stand the blow and have no ability, so you'd better stay at home, which means you hate iron and never produce. Canaries are usually kept in captivity because they are fragile and can't stand big twists and turns or blows.

Canary, also known as hibiscus, hibiscus, white jade, white jade bird, bluebird and Bai Yan, is a cereal-eating bird in passeriformes. Originated in Canary, Madina, Izuriz and other islands on the northwest coast of Africa, it is a captive ornamental bird with excellent feathers and good singing and dancing. There are 24 species, which are listed as one of the precious caged ornamental birds at home and abroad. Although China began to introduce from abroad in the 1940s, it has not paid attention to the maintenance of varieties and strains, and there are not many pure breeds at present.

Extended data:

Feather colors such as yellow, white, gray, green, orange, bronze, cinnamon and colorful appeared after artificial breeding. Its body shape and posture have also changed greatly, and different strains have appeared after artificial cultivation. The upright, big crescent and upright eagle cultivated in recent years are especially precious.

References:

Canary (a bird of finch family)-Baidu Encyclopedia