I've never treated sour crop with garlic, and I can't say with authority that it won't work. But I suggest using a tried and true anti-yeast treatment as sour crop makes a chicken feel very sick and miserable, and you don't want to prolong that.
Miconazole vaginal anti-yeast cream is what most folks use for sour crop. It's easy, inexpensive, and it works 99% of the time. You can also use Medistatin and acidified copper sulfate.
Miconazole vaginal anti-yeast cream is what most folks use for sour crop. It's easy, inexpensive, and it works 99% of the time. You can also use Medistatin and acidified copper sulfate.