The iPad 3 & 4 share the same battery...see [product|IF116-001-2|here]. If you want to confirm if the battery is causing the charging issues, you could try to run a utility such as coconutBattery (Mac) or 3uTools (Windows). These utilities will check the battery and report it's design capacity. Anything below 70 is ripe for replacement and anything lower than 60% will definitely need to be replaced.
IF the battery is not the issue, check with different cables and charging bricks. Apple original or high quality MFi accessories are strongly recommended. If none of this solves the problem, then you may have a damaged charge port in the device or a logic board issue