I believe this "send to management" idea will create hierarchy issues within your team and will limit your employees providing honest feedback to the "management"

Try this;
Each Friday afternoon work stops for 2 hrs. Everybody gets together, office turned to a social venue. Sandwich, Pizzas, Drinks (arrange as you wish) afternoon tea or even lunch
-First two weeks nobody will speak but its your job to open the conversation, talk and ask questions. They must be comfortable. Answer questions in front of them so they are comfortable approaching you, avoid confrontation reply later in private
-Talk about the past week, figures and plans next week, talk to top performing employees, share their story, tell a funny story from last week, talk about markets, share your opinions
-You can ask to prepare questions submit before the meeting or they can ask you during the meeting
-After a month this becomes a ritual, people will need to brings cakes etc,... team spirit.. ideas will flow and have a great impact on your business
-Be careful, if people asking questions about how to do their job, there is a training problem.
-if you are looking for a online survey, just buy one of from internet..if you are looking for a real-time chat platform buy one of from internet, if you are looking for a mail distribution use your email client
-Your employees is everything to you, make sure you interact with them