Most often, disability is not earned income but it may be taxable. It is considered earned income if disability is reported on W-2. https://www.irs.gov/publications/p907/ar02.html#en_US_2015_publink10008633
As far as foreign disability - it depends. It is never taxable when payments are proceeds from disability insurance that was paid for (purchased) by the employee.
However, employer-paid short or long-term disability it is taxable depending on the treaty country. Generally, it may be taxable because the employer deducts it as an expense. If it is taxable in the foreign country, it is likely taxable in the US. However, any foreign tax paid will be credited against your US tax liability. If it is expressed on foreign employer pay stub it is also likely to qualify for FEIE. If it is social security type disability - then this is not qualified for FEIE.