I have been thinking about having a few chickens for our own eggs, we live in town but can have 2 or 3 more if we pay a fee. I am just concerned about a few things.
We have 2 big dogs. Also, what about winters, and leaving for vacations etc?
I just don't want to take the plunge and find its more work than I want to have to do. Or the dogs hurt the chickens, etc.
Probably my biggest concern is wanting to let them roam the yard, so they aren't pinned in their whole life. I have flowers, and plantings, and have heard chickens will eat about any plants you have. ??
Just wanting to scope things out before actually taking the plunge. Thank you for any advice you can give me.

Welcome to the BYC forum.
There are many reasons to have chickens, but we all live in different situations. You have mentioned a number of concerns, so it's good that you are thinking about those before you get your chickens.
Dogs and chickens don't always go together well. If you have chickens, you need to protect them from your dogs. This means a fenced in chicken run for most of us. One that keeps the dogs out and the chickens in. It is recommended to have 10 square feet per bird in the chicken run.
Chickens don't need to free range to be happy. They do just fine in a chicken run. I have my chickens confined to a chicken run that is covered with bird netting to protect them from hawks and eagles. I would love to just let them free range all over my yard, but I know that by the end of the summer they would probably all be gone from predator attacks.
Chickens don't require much care. I have 10 chickens and it takes me maybe 5 minutes per day to care for them. I have a 3 gallon waterer and a 5 gallon feeder (that I half fill) and those have to be refilled about once every 10 days. So, not very much work. But, it is a daily chore to check status of food and water, to collect eggs, and to let the chickens out of the coop in the morning and lock it up at night.
I would not plan on any days long vacations unless you have someone lined up to check on your flock while you are away.
Chickens will eat just about anything, but I don't free range my birds so I don't know if they would eat flowers and plantings in the garden. Maybe someone else can answer that for you.
With 3 laying hens, you will probably get 1-2 eggs per day on average. We all love those fresh eggs from our backyard flock, but is it worth your commitment when you can probably buy a dozen eggs at
WalMart for less than $1.00? If you are keeping chickens only for eggs, then you will soon find that you have committed a lot of time and effort for a small return. Most people here will be honest with you and tell you that buying commercial eggs is a lot less expensive then keeping a backyard flock for eggs.
So why do I keep a small backyard flock?
I keep a small backyard flock of 10 chickens first and foremost for the entertainment value. I just like having them. Stress relief, if you will. Good for the soul. Second, I have them making compost for me for my gardens. Chicken compost is great for that. Third, we recycle as much "waste" into my chicken project as we can to save things from being sent to the landfill. All my organic yard waste gets thrown into the chicken run (grass clippings, leaves, chipped wood, etc...) and we also feed almost all our kitchen scraps and leftovers to the birds instead of throwing it out. I also shred all our papers, newspapers, and cardboard and use that as litter in the chicken coop. We used to have 3 or 4 bags of garbage thrown out every week, now we only have about 1 bag per week. Not all of that is due to recycling with the chickens, but when you shred all those paper products, you certainly reduce the bulk in the trash bags. Almost no food waste is ever thrown in the garbage. Finally, as a bonus, we get fresh eggs. I currently average about 6 eggs per day, but in the dead of winter, I was only getting 1 or 2 eggs per day. When it's -40F outside and you have to go check on the chickens 3 times per day for 1 egg that might be in a nest box, that is when you really know if you are committed or not. I never tried to fool myself into thinking that I needed chickens for fresh eggs.
So, only you can decide what is best for you. I hope you get lots of responses to consider your options. Best wishes.