Depending on what causes them, brown spots can definitely come back in the spring. Even if you treated your soil with special formulas like a good chicken manure fertilizer to initially get rid of them, once springtime comes, some of the brown spots you eliminated might appear again, causing your young grass blades to already appear unsightly and sickly.
Now, brown spots can be caused by a variety of things, and you could have addressed some issues last year, but not others. Some possible causes include uneven fertilizer application, pet urine, certain types of fungi and even insect infestations. With insects returning in the spring, it stands to reason why the formula you used to correct any uneven fertilizer having been previously applied might not have worked.
As you notice brown spots returning, it’s very important to look at the issue more closely and identify the real culprit, especially if you already tried various methods and they didn’t work. Also, if you’re going through a difficult time and you’ve already reached a dead end in your research, consider consulting a gardening expert and asking them additional questions, or even having them over to inspect your lawn themselves. You’ll find it will save a lot of time and provide you with the right answer right off the bat.