I bought pet feeding bottles for TLK. However, the nipples were very stiff. Even with a much enlarged hole, the amount of effort required to produce contents from the bottle through the nipple were such that I did think that TLK could successfully suckle from the bottles. So, I used a large plastic medicine dropper that I had.
When TLK became constipated, and I thought mineral oil could help, I bought additional medicine droppers to use for the mineral oil: these were in a blister pack, glass, with one straight tip and one bent tip. I got to thinking about it, after a few days (I am very slow) and realized, if something happened to the plastic medicine dropper, I would be stuck. The glass droppers would do, but not as well as the large plastic dropper.
I was in a grocery store last night, (a local chain that does a lot of community service, http://www.unitedtexas.com/) and amongst my list of to look for items was a medicine dropper. I could not find one, so asked the pharmacy technician. He informed me that the store gave those away, and they gave me one. Wow!....