Build that fence!
Most estimates state that a family of 4 needs 2 acres of land to be self-sufficient. That's the upper limit I've seen (with a couple exceptions). It's a lot more efficient when you have 25 families of 4 working together, you can grow year round in the tropics, and they have food from the ocean as well.
Assume at most the settlers require 50 acres for fields. This is very high and it's more likely to be closer to 25 acres.
A 50 acre circle has a circumference of 1600 meters, or one mile.
A 25 acre circle has a circumference of 1130 meters, or .7 miles.
Wooden fence posts plus barbed wire would be the best choice for a fence to keep out dodos. Since there is a tropical forest and they're allowed "as much wood as they want" the posts are the easy part.
Barbed wire wasn't invented until the mid to late 19th century. But wire fencing was available earlier and people did add sharp pointy things to it to make it hard to pass through. It's unclear to me if your settlers have metalworking to produce wire (they presumably have basic metalworking) or enough raw materials.
Thorny bushes are the other option. It's probably what the people who already live there use. Put in the posts and use wattling and some wire to contain dead branches of thorny trees and bushes. Plant seedlings of the bushes so you won't have to replace the dead branches for more than a few years. Combined with some wire, this will be unstoppable.
A mile of fencing is very easy for a village of 100 people to maintain. It's also fairly easy to build, once you have the materials. One full day's work for 1/3 of the village. Cutting the trees and making the posts is not time consuming. The metalwork is the bigger deal.
If you use barbed wire fencing, here's an estimate for materials to do 1/4 mile. Multiple by 3 for your smaller field and by 4 for your larger one. These are for modern materials and your settlers can get away with a lot less here.
4 8-inch wood posts
57 4-inch wood posts
55 6 1/2-foot steel posts
10 pounds staples & clips
6,600 feet 12-gauge barbed wire
39 hours labor
If you need to build a wooden fence, add wire! You can still use the wood for structural integrity but add the wire so the dodos don't peck through it. Or use other metal. Old rusted pieces of metal work great. Anything the community might otherwise discard.
On the outer side of the fence, whatever you build, add shells. You'll already be eating a lot from the ocean and you will have shells. Break them up so they're sharp and unfriendly to unshod dodo feet. Start with a thin line around the outside of the fence. Every time you have a pile of crushed shells to fill some buckets, send the kids out to add to the line.
Make sure you have a couple of very well-built gates and you're all set.
Store your harvest on elevated platforms.
Build wooden platforms high enough so the dodos can't jump up or reach with their beaks. This should still be low enough for village adults to reach with ease.
If you have it, bamboo would be a great material here.
Add wire, shells, rusty metal, etc to keep the dodos from just pecking through the platform legs.
Bonus, this will reduce (not eliminate) rot from damp ground and insect infestation.
(This is a child's play structure but it's about the right size and shape. Store the ladder separately, if needed.)