Well, to be honest Khadiga, it's difficult to know where to start - there's so much to admire about this. I'll try left to right and top to bottom

The old henhouse has a good feeling of depth, due to its darkness. Personally, I would have darkened the areas between Robbie the dog's legs, and maybe removed some of the clutter. I find it's dragging my attention away from him. If the inside of the henhouse is as dark as you depict, would Robbie's back paws be as light as his front ones? The same applies to the floor beneath his back feet - it's too light for the situation, as it would be shaded by Robbie's body. With that area darker, your eggs would be displayed better too.
Robbie himself is lovely! He's a proper hairy Border Collie puppy. You've maintained the cheeky "smile" that I intended him to have, and his eye (the focal point) is nice and bright.
We often unwittingly suggest human expressions when drawing animals. Here, I feel the highlight above his eye is suggesting a quizzical expression - slightly worried rather than having fun. I would have opened his eye up slightly, by lifting the top eyelid, to give him a more fun-loving, wide-eyed look, and rounded off the top of that highlight, so it formed a curve instead of an upward-pointing shape. But quizzical works well too
I mentioned your henhouse during the course, but it does have a great feeling of age, character and dereliction.... Actually it was so old and beyond repair that I reluctantly pushed it into a bonfire with my tractor a few years ago.
The wood below the jutting nest box is perfectly balanced. It holds interest when viewed directly, but is not detailed to the point of distracting the eye and taken the focus away from Henrietta the hen.
Bottom left now:
Time spent on the weeds here would have been worthwhile. I like what you have done, but they lack a natural sharpness. If you'd just concentrated your time on a few chosen foreground leaves, you could have used your less-sharp drawing behind them. As it is, my eye has nowhere to focus, so the area loses depth. And, with no clearly-defined highlights, everything appears to be on single plane. This is particularly true of the area below the towing ring, where the weeds have no defined background at all - just flat shading. You could have quickly used a technique I teach in my physical workshops in that area - drawing random shapes with dense blacks in between them and then shading the whole area until it began to disappear into the shadows. That would break up the flat tone and suggest depth with very little work. Remember, not everything is perfectly understandable in Nature, so a "suggestion" of something in that area (and beneath the henhouse in general) would do very well.
I like your positively drawn grass in this drawing. It works very well - especially with the blended suggestion of ground.
The wheel has near-perfect ellipses and a feeling of solidity and reality. The central boss and washer and split pin are all well-studied too. And I like the way it's firmly connected to the ground by being slightly embedded in it.
The weeds around Henrietta - the same applies as above. It's a good try but they suffer from a lack of sharp edges, and depth in the background behind them.
Henrietta is superb! Her eye is wonderfully clear and contains the darkest tone in the area, so my eye is immediately drawn to it - which is just as it should be.
I think you've achieved a good balance between the feathery texture of her body and a need for it to not dominate.
I would have liked to have seen her more rounded three-dimensionally. A few stronger tones or areas in her body would not have drawn attention away from her eye. More highlight on the top of raised thigh would have added form to it too. That raised foot and leg are important to the story, so I would have worked to emphasise it.
I noticed you drew the lower half of Henrietta before you drew the background around her. That may be why her lower half doesn't quite stand out from it as much as I believe it could. But that's nothing that a little readjusting of tones in her couldn't solve. You could try brightening her highlights (especially on her raised foot) and darkening the darker areas. However, I suggest you don't - just put it down to experience and carry it over to your next drawing.
Overall, I'm extremely pleased to see you create this. You should be very proud of it.
I thoroughly enjoyed working with you and do please continue with the good work.