In my opinion, this the best solution for the wall and roof, if the bales are tightly pressed. Much much cheaper than logs wall. Use logs just for poles and roof frame and that it is.
For plastering is indicated yellow clay mixt with horse dung, or animal hair, or very small chopped straw, or sawdust...
First layer one part clay, one part horse dung, one part sand,
water, and chopped straw as it contains, sifted to get out a fine paste. About 2-3 cm. Second layer the same combination plus one cup of flour mix with one cup of water, and on the fireplace another four cups of water . This cold quantity is about 5 buckets of the 10-l mixture. Do not leave the clay so prepared for more than 2-3 days for it will smell bad from flour.
At last, just clay, sand one part or two or three, depends on the quality of clay ( the paste must be sticky). Yellow earth is put to soak for at least two days. Dung is used fresh.
The material obtained must be sticky, creamy and not crumbly. The last layer doesn't put the straw.
How to fix strawbale ...