A slack warp, threads set too closely in the reed, or increase of friction on the first foot or so of the warp where the threads were handled all cause poor sheds. Fuzzy yarns like mohair can also cause a poor shed.
In weaving, poor shedding occurs when the warp is too tightly wound, causing threads to be closely packed in the reed. This can also be caused by excessive friction on the initial section of the warp or the use of fuzzy yarns like mohair, leading to inadequate shedding.