According to a Chinese report Apple is cutting back even further on their production of the iPhone 5c. Assembly partner ProTek (Pegatron) has cut production to 80,000 units a day from 320,000 units in October, and Foxcon is currently producing 8,000-9,000.
This is probably due to the high demand of the iPhone 5s. A data graph from Fiksu shows the iPhone 5s is 6.4% of all iPhone usage and the 5c is coming in at 2.1%. The iPhone 5c supply is readily available as for the iPhone 5s is showing 1-2 week shipping time from Apple's site.