Ionic - plugins not being added to ios folder

Starting with a fresh ionic install and then adding plugins, they are not added to the ios folder. I tried ionic prepare which results in add to body class: platform-ios but it does not add the plugins to the ios directory and results in this error:

CompileXIB moodtracker/Resources/DatePicker.xib
cd /Users/tomchambers/projects/moodtrackerApp/platforms/ios
export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/Users/tomchambers/.rvm/gems/ruby-2.1.2/bin:/Users/tomchambers/.rvm/gems/ruby-2.1.2@global/bin:/Users/tomchambers/.rvm/rubies/ruby-2.1.2/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin:/usr/local/git/bin:/Users/tomchambers/.rvm/bin:/usr/local/mongodb/bin"
export XCODE_DEVELOPER_USR_PATH=/Applications/Xcode.app/Contents/Developer/usr/bin/..
    /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/ibtool --target-device iphone --target-device ipad --errors --warnings --notices --module moodtracker --minimum-deployment-target 6.0 --output-partial-info-plist /Users/tomchambers/projects/moodtracker/platforms/ios/build/moodtracker.build/Debug-iphonesimulator/moodtracker.build/DatePicker-PartialInfo.plist --auto-activate-custom-fonts --output-format human-readable-text --compile /Users/tomchambers/projects/moodtrackerApp/platforms/ios/build/emulator/moodtracker.app/DatePicker.nib /Users/tomchambers/projects/moodtrackerApp/platforms/ios/moodtracker/Resources/DatePicker.xib
/* com.apple.ibtool.errors */
/Users/tomchambers/projects/moodtrackerApp/platforms/ios/moodtracker/Resources/DatePicker.xib: error: Interface Builder could not open the document DatePicker.xib" because it does not exist.

** BUILD FAILED **


The following build commands failed:
    CpResource moodtracker/Resources/CDVNotification.bundle build/emulator/moodtracker.app/CDVNotification.bundle
    CompileXIB moodtracker/Resources/DatePicker.xib
(2 failures)
Error: /Users/tomchambers/projects/moodtrackerApp/platforms/ios/cordova/build: Command failed with exit code 65
    at ChildProcess.whenDone (/usr/local/lib/node_modules/cordova/node_modules/cordova-lib/src/cordova/superspawn.js:135:23)
    at ChildProcess.emit (events.js:98:17)
    at maybeClose (child_process.js:756:16)
    at Process.ChildProcess._handle.onexit (child_process.js:823:5)

The only way I've found to make it work is to completely delete the ios build folder and do cordova platform add ios which will readd it with the plugins. This seems very inconvenient.