We get our dogs together and Hunt the thickets and hedges once a year. Basically the various lease holders do a round robin invitational. Most every weekend in the fall someone is hosting a hunt. Mostly Hare, Rabbit, Pheasant and Fox, occasionally Hogs.
We often have 20-30 dogs. Nobody puts a vest on their dog unless we are Duck hunting. Most everybody has break away reflective collars and/or break away Flea and Tick Collars.
The reason being, if they take out after a Deer (which they are trained not to do, but stuff happens) they may get hung up by their vest or collar and you may have no idea where to start looking for them.
Years ago one hunter lost his dog this way, eventually found it weeks later, hung up by it's collar, dead. The break away collars don't come off that easy, my dog loses his about every other hunt.
Most Dogs avoid Blackberry thickets or thorny bushes (somewhat), except when they are in hot pursuit. Stuff happens, the up side is they seldom injure their eyes. We pulled a four inch stick out of the chest of my Daughters GSP. Running through a barbed wire fence in hot pursuit, has torn up many dogs.
Brushing or combing your dog after a hunt and/or a bath is a must. My finger tips are sensitive (and years of practice), I rub down (massage) the whole dog with my finger tips, I can pick out 90+ percent of the Ticks. Personally I'll never own another long haired dog.
One Shot works OK, Bayer Tick and Flea collars work best for me. Be careful not to overdose your dog on Flea and Tick stuff, it can happen, they go into convulsions.
If you do decide to put a vest on your dog, find one that doesn't trap a lot of heat. Even near freezing, working Dogs often over heat.