My beds were burned ! (And now the chickens are coming)

Oh, dear, Snohare - this does not sound promising at all. It sounds like the landlady is making it hard for you for some reason - do you think she regrets letting you have the plot? Is this an informal agreement and do you pay her for the privelege of getting your stuff burned and providing free meals for the chickens? Do you at least get some of the eggs. It sounds like you need to create a chicken run round the outside of your plot - and as for the soil, you may need to do container growing on the top rather than dig down to any usable depth.
But it does not sound good at all - could you start trying to find somewhere else?

Ditto Jeanied's comments - it doesn't sound good. Can you make do with growing in pots for this year? Sorry it sounds as if you are being seriously mucked around. I think your landlady is a daft mare and her boyfriend is a .................................... (other Grapes can fill in the blanks)

I'm not sure of the background regarding this, but it does sound as though you are going to be on a loser no matter what you do.
I would suggest not doing anything on this land, it will cause more trouble than good in the long run.

To be fair, my (very nice) landlady is what is known in social work circles as "a vulnerable person" - even her issues have issues - and after a series of lodgers from Hell, her overprotective boyfriend simply jumped to the wrong conclusion when he saw me sleeping during the middle of the day. He is actually a really nice guy, just fed up of seeing her taken advantage of.
A day or two later when he saw I had handmade a new gate his attitude totally changed and he decided I was a good guy, which has set the seal on my acceptance here. He did apologise later for burning them and casually said "I'll buy you more", meaning it no doubt - as he was very successfully getting me drunk at the time I wasn't worried !
But they were made of century old larch inch thick tongue and groove heartwood (old floorboards from Braemar Castle), and even if he realised the disaster he had visited upon me - I was relying on having those for a good few years - there is no way to get anything similar locally. We live a long way from anywhere that would deliver wood.
And besides, I had my revenge...albeit unintentionally. I must tell you the story at Grapestock, it's not internetable.
Life here is nothing if not exciting...you could make a sitcom out of this situation, I kid you not.
I get free eggs from the chickens, and life here is pretty idyllic apart from the occasional minor kerfuffle, usually due to a panic attack or farcical failure in communication.
But must I keep all my seedlings out of reach of chickens ? Because if so, I must go start digging yet another garden I have been offered. <sigh>

Sounds rather confusing, rather you than me.

Chickens will destroy anything, in literally minutes.

Hmmm, Snohare - rather you than me, mate! In my book life is complicated enough without getting embroiled with people with issues!

That was exactly what I was needing to know Womble, ta ! <shoulders tools and marches off up hill to another spot>
Yes Jeanied, I am treating it very much as an educational experience. Now I understand much better the idea of emotional "collateral damage" and how nice people can fall out bigtime due to simple lack of communication skills.
But hey, my dog has en-suite hounds to play with, most importantly we humans have loads of goodwill towards one another, and the eggs are tasty...

See if you can get some old rabbit runs - try free ads/freecycle. They'll be about 2' tall and various sizes (paint them all the same colour to look neat) and should generally be light enough to lift easily/have opening tops. That will cage your veg cheaply and protect it from the chickens