Respiratory Illness Medication and Progress Questions

Hi! I am new to this board, and new to chickens in general. Last Friday (four days ago) I was given a small Polish hen, with an obvious respiratory infection. She was bubbling, gurgling, lethargic and had a snotty nose. I went to the feed store, and was sold a soluble tetracycline powder, that can be used, so the package says, for chickens, pigs, turkeys, etc.

Unfortunately, the instructions tell me that the solution must be replaced each 12-24 hours, and only provides mixing instructions by the gallon. Well, my little hen clearly is not going to consume a gallon each 24 hours, so I have been mixing it by the cup, but my measurements are likely imprecise, given that I do not have a scale capable of measuring so small an amount of the powder, to make only a cup. I have been taking the approach that a stronger solution is better than a weaker one, so as not to create a bacteria that is resistant to the tetracycline.

I am instructed, by the package, to give the solution for 7-14 days.

These 4 days later, she is alert, hungry (very hungry!) and the snotty nose seems to be cleared up. She is living in a small cage, in the kitchen, much to the delight of our cat, but not to the olfactory liking of my family. She seems to be on the mend, alright. But...

She snores. She does not do it all the time, the way she did when she came. But, still, she snores. I have read on this site that some chickens just do that. Of course, I do not know this hen well enough to have any idea whether this is normal for her. I will, of course, continue with her treatment for at least the full 7 days. But, I would really love to have her live outside, apart from our other chickens, but out of the house where her fragrance is becoming ... off-putting.

So, my questions are these:
1. Are there breeds which snore more frequently than others, such that I might assume that this polish hen is just a snorer, and not that she is drowning in her own juices?
2. Since she has four days of antibiotic in her, do you thing she could withstand the outside night air? We have not had a freeze for a while, but it is clear and cold at night.
3. Do you think she is still contagious? I have one hen who lives very happily with our two lambs, and snuggles with them at night. If this hen is not contagious, she could live with them, which would eliminate the cold problem, I think.
4. Finally, any advice for me concerning making the solution, in terms of measuring the powder? The package contained 6.4 ounces, and would have mixed up 12 gallons, of the strength indicated for this hen. I can do the math, but do not have an instrument that will allow me to weigh out the precise amount of powder. I will have to eyeball it, unless someone has faced this, and has a volume measurement that they can recommend to me.

Whew! That is a lot to ask of y'all on this first post, but I appreciate the chance to present it to you! Any thoughts will be appreciated. Thank you so very much!!

Patience