I dreamt of huge number of different healthy animals under huge roof, being vaccinated, bandaged (like mummies) , being prepared to be transported to another country... what this could mean?

It's always best to know something about the waking life circumstances that generated the dream so as to be able to properly connect to dots. However, the meaning of the symbols should help guide you. Here are links to the definitions of those symbols on this website:

animals: dreamdoctor.com/index.php?option=com_dre...y&task=details&id=64
castle (var of being under a huge roof): dreamdoctor.com/index.php?option=com_dre...&task=details&id=391
illness (var of need for a vaccine): dreamdoctor.com/index.php?option=com_dre...task=details&id=2088
clothes (var of wrapped like a mummy): dreamdoctor.com/index.php?option=com_dre...&task=details&id=493
journey (variation of preparing for a long trip): dreamdoctor.com/index.php?option=com_dre...task=details&id=2089
foreign country: dreamdoctor.com/index.php?option=com_dre...&task=details&id=848

Another way at the meaning is to take into considerations your feelings IN the dream. Feelings in dreams are never disguised, so how you feel in your dream is how you feeling about its subject in your waking life. Were you scared, disturbed, curious, amused in the dream? If so, try to ID where in your waking life you were feeling that way just before you had the dream.

Without knowing what was going on in your waking life, it's hard to say with certainty how this dream specifically relates to your waking life. But, this dream might reflect your feelings about a graduating class in high school (health animals) being prepared (vaccinated) to go off to college (foreign country). Or, it could have to do with another "healthy" group of people you know who are having to undergo some sort of preparation (inoculation) which you feel is over the top or confining (being mummified) in preparation for a big journey or enterprise to a foreign or unknown place.

Hope that helps!