The U of I is probably a little different than other schools. For 4th year, you have quite a few mandatory rotations you have to take on campus. Beyond that, there's directives and electives that you can take. Directives are a bit more career focused and electives are whatever you fancy, you can go do as long as it's educational. The school has a super long list of previously approved externships for literally all over the world. There's approved rotations in Germany, New Zealand, India, Taiwan, and other locations. If something you want to do isn't already on the list, prove to them it's educational, and by that they mean help you advance in your knowledge to be a better doctor, and they'll let you go do it.
As far as professional development, because U of I does rotation quarters in previous years, you actually start your 4th year the week after spring break in your 3rd year. You're a 4th year on needed rotations to graduate until March of the next year. The last 8 weeks before graduation is all professional development. Any rotations you wanted to take on campus but couldn't get in, start working (though there's been debate about this one), or do more off campus rotations of anything you want. It's completely up to you.
https://www.avma.org/ProfessionalDe...cc-student-externships-special-interests.aspx <-- That is a very long list from the AVMA for a bunch of summer and/or 4th year externships that you can do. The faculty also send out a massive amount of emails for summer externships and residency/internship programs. You'll also probably become familiar with a lot of the professors who, usually, are thrilled to help you find stuff like that in your field of interest. The school itself has a exotic residency in association with Brookfield Zoo and Shedd Aquarium. You spend 1 year at each of those locations and 1 year at the school working in the WEAMS department. As far as networking, there are so many symposiums throughout the year that you'll meet plenty of people in your field of interest to talk to. Along with the big SAVMA one, there's a bunch of exotic symposiums throughout the year. Our exotics department disappears in the fall for one all the time.
I hope this helps you with your questions and if you have anymore, just let me know.