Lifeguard is spot on , never try to recharge a dry cell battery , alkaline or otherwise .
I'm presuming you have a feeder that takes a 6 volt square lantern battery , most do . In that case get a solar panel from the company that makes your particular model , or from a source that clearly states what they are rated for .

Example:
I have an American Hunter "barrel on legs" style feeder , it takes a 6 volt lantern battery and has an option for a solar panel . It didn't come with either , so I bought a 6 volt rechargeable battery from Sportsman's Guide for $10 , and a solar panel rated for 6 volts peak output for $20 from Bass Proshops . American Hunter sells both , but didn't have the lowest price , the other two sources generally have them all year around . Problem resolved .