I have two new Kiko does that have both kidded last season and have spent the last month with a buck. Is there a simple way to tell if either are pregnant?
Since the cycle about every 18-21 days on average, and they've been with a buck for over a month, odds are very good that they've been bred. Aside from an ultrasound (too early yet) or a blood test (not 100% accurate), just keep your and wait for them to start "showing"... with twins, they should start "plumping out" around 3-4 months. Good luck!
If you can pull blood, you can send it to Biopryn and have a pregnancy check. According to Biopryn, “it is greater than 99% accuracy when the assay identifies at least 30 days post breeding”.