I think a more effective (and easier, enjoyable and risk-free) way of getting it into them at this time of year might be;
- find a container that will hold about as many pellets plus a few treats of corn and maybe a few sunflower seeds (10%) which the hens will readily eat in one go if made into a nice soft warm mash. Measure out this amount X 7, add a little oil to some of the pellets and mix in the correct amount of Flubenvet for your number of hens in the usual way, gradually adding the pellets to the treated starter mix as you go. For each two full-sized hens you will need 1 level scoop of powder.
-each day, late afternoon, measure out and moisten one day's worth of the mixture with hot water until just nicely crumbly, and spread it out on a big plate.I use a large heavy pottery saucer, the sort used for putting under a big plant pot. I also place the plate on a concrete block so the mix doesn't get scratched off into the litter. You need to allow enough room for them all to gather round and gobble down their share - with more than five or six hens you may need two feeding stations. You can see the stuff going in, the hens love it, and there's none of the stress and risk involved in mixing it with oil and squirting it down their throats. It's so easy to get them to eat Flubenvet that I really can't see why the squirting method should ever be necessary, actually. If you only need to treat one hen, just separate her and give her a private treat on her own.
Mine are getting this mash, minus the Flubenvet, every day now it's winter, and all are going to roost with lovely full warm crops to last them overnight.