spring rush

This is from the Panhellenic website:

The following chapters are eligible for Continuous Open Bidding (COB) as of 11/4/2013: Alpha Delta Pi, Alpha Omicron Pi, Chi Omega, Delta Delta Delta, Gamma Phi Beta, Kappa Alpha Theta, Sigma Kappa, and Zeta Tau Alpha. It is up to each individual chapter's discretion whether or not to hold recruitment events in the Spring.

Delta Gamma unfortunately isn't able to recruit new girls (you could always email in their membership VP to see if this has changed, but I do doubt it.)

There is a way for them to check and see if you dropped, but chances are they wouldn't do it. There also may a chance that a girl in that house remembers you/your name, and she voices her concern, but this is unlikely.

I would go to the spring events for the other chapters you did like. I know Theta, SK, Gamma Phi, and Zeta have their dates/events listed on their websites. I can't speak for other houses though. If events conflict, try and prioritize house tours and preference events over philanthropy/mixers.

they can check if you dropped, but most wont think anything of it (a lot of people drop during fall rush). If a girl does remember you, which might be unlikely because they met so many girls and it was a long time ago, you can just use it as a conversation point and explain that you dropped in fall but you're more committed now.