Well, At least for the chickens, after that restart thing that just happened in skyblock, I was able to get more than 10 chickens. It appears the island wasn't counting the chickens that were spawned before the reset/kick. So It let me spawn 10 more.
This issue has been added to our JIRA and will be looked at within 24 hours. An update will be posted to the thread when fixed by @JamieSinn
@JamieSinn has stated that we may potentially fix this in the future with mob stacking plugins. At this time we cannot fix this as every server restart, the limits reset.