My villagers don't trample my crops but recently, they've been trying to harvest them like the crops are their own and it's extremely annoying because they often replace my crop with a completely different one! I tried to prevent that from happening by putting iron doors in the outsides of all my structures but somehow a few of the learned how to open the doors so the problem continues. I have resorted to killing some of the villagers but I don't want to have to kill some of my higher level villagers because they have some very useful trades I can take advantage of for my next big projects in that particular survival world. I play on bedrock edition 1.14 on Xbox so the villagers really have better trades. Also, I had expanded my village by adding 20+ small cube buildings in hopes to having more villagers to trade from (which worked but overpopulation has caused many issues such as this one). Now, with having twice the amount of villagers as before, there are also that many more iron golems. What do you guys propose I do? I have had to make multiple modifications already to more than one of my farming facilities. I want to know if any of you can come up with an easier solution than than destroying all the extra buildings I made and killing over half the villagers and fighting the now 6 iron golems.
Unless you have actually seen the villagers use the buttons for you iron door, I highly doubt that they opened them themselves.
So there are a few reasons why you might be actually facing this problem:
There is a spot where the villagers can hop into your farm. Those can be tricky to find, especially if you build fancy "natural" looking borders instead of just putting walls there.
Your door gets activated by a device that can randomly activate in a uncontrolled manor. This includes presure plates (villagers running over them and then pathfinding to the now open crops), wooden buttons being shot with arrows from skeletons, weighted pressure plates by any random drop, or many more. My suggestion is to just use a single stone button or something else that only a player can use, like a specific key card system.
Hope this helps.