If I go to the nether all my villagers die

I went to the nether to go mining for ancient debris and when I got back my villager enclosement, it had nothing in it except some rotten flesh. This leads me to another point which is Zombies drop rotten flesh. But my villager enclosement is lit up and perhaps the zombies  were able to glitch through the glass roof. idk someone help me i losing my villagers.