Chawki rearing refers to rearing of young silkworms, from egg hatching up to the second moult stage, under controlled micro climate. The process of chawki rearing may be compared to nursery raising in horticulture and plantation crops. The purpose of chawki rearing is to grow quality silkworms under disease free environment, to reduce worm rearing duration, cost and to improve cocoon productivity at farmers’ level. Quite often, the worms are affected by pests and diseases at the very young, vulnerable stage due to poor hygienic condition, especially when the rearing house is part of the farmers’ dwelling house. This apart, many farmers have difficulty providing suitable microclimate for hatching of eggs thus compromising on the quantity and quality of worms and, at times, resulting in staggered hatching and loss of worms during brushing (separating worms from eggs). This leads to poor cocoon yield. Also, the process from eggs to cocoon harvesting takes about 30 days involving cost of pest and disease management as well as feeding the worms with mulberry leaves.
Mulberry silkworm rearing, being completely domesticated, demands specified environmental conditions like temperature (24-28 0C) and relative humidity (70-85%). It is therefore necessary to evolve measures for economic cooling through selection of proper material for wall and roof fabrication, orientation of building, construction method, design, etc. Further, enough space must be available to carry out leaf preservation, chawki rearing, late age rearing and moulting. It should also be convenient enough to conduct effective cleaning and disinfectionThe size of the rearing house depends upon the quantum and type of rearing. A floor area of 400 sq ft. can provide rearing space for 100 dfls (dfl: Disease Free Layings; 1 dfl = 500 larvae)