The foreign aid organizations managed to get the donated (mostly by the U.S.) food to the 600,000 refugees (Sudanese, Central African Republic and Chadian) in camps throughout eastern Chad, before the rainy season turned the dirt roads to impassable mud. In the last year, the U.S. donated 2.8 million tons of food, worth over $1.3 billion, to hungry people all over the world. Dozens of other foreign aid groups arrange for distribution of the food in dozens of countries. But Chad is one of the worst "hunger hot spots". Partially because of persistent drought in the semi-desert area (just south of the Sahara desert), and partially because of the banditry and political violence that has been made worse by Chad and Sudan financing each others rebels.
In the last decade, oil wealth has become another destabilizing factor. Two years ago, there was $1.2 billion in oil sales, and that is growing. Before the oil, there was much less to steal (foreign aid, small amounts of taxes) if you controlled the central government. Now that prize is much more valuable, and more groups in the country (with dozens of tribes) are arms and negotiating to get their hands on the cash.
The current government is aware of the competition, and is expelling potentially hostile (from other tribes) from the capital. Entire neighborhoods are being emptied and the buildings destroyed (leaving cleared land.) In one of the more notorious examples of this, 3,700 buildings were leveled in just one neighborhood. Some 50,000 people appear to have been driven out of the capital, many of them heading for neighboring Cameroon.
August 31, 2009: A Greek aid worker, who was kidnapped on August 4th, was released. It is unclear who was holding him, and what for. But several foreign aid groups have pulled out of Chad over this, and similar incidents. This has led to a reduction in the availability of medical care (foreign aid groups provide most of it in eastern Chad) and other services. This often motivates the local tribes to crack down on violence against the aid workers.