Unless you have a lot of extra space to hang a large number of blankets and coolers (which most barns don't) they will quickly start to be in the way. I didn't realize this when we first opened our barn and our first full year had many surprises and this was one of them. I didn't have any place to put all the blankets at my barn. On top of all the winter blankets that were at the barn, I also had day sheets and fly sheets coming in as the weather turned warmer and the bugs came out. It was blanket overload to say the least.
Give a time frame and be direct and clear
The best way to clear out your barn is to give your boarders a time frame on when everything needs to be gone for the summer. Be very specific about what can stay and what needs to go. Explain to them about the limited space and in order to make room for summer equipment, summer sheets and fly sheets the winter stuff needs to go home. This is a very fair request and it will make your job so much easier. Having blankets all over the place will not affect your boarders but it will make your job more difficult when you are trying to work around them.
I send out a letter to everyone about cleaning out everything and I give a deadline date. I will also call or text reminders to those that have not done this as the date gets closer. You might have a couple of boarders that become annoyed but that is okay. This is part of running your business and you shouldn't have to work around a mess of blankets and all that goes with it. Most of your clients will be very good about taking care of this but sending out a letter with a specific date will make it happen much faster and with very little nagging from you. Remember that it's not personal, it is business.
Spring cleaning is something that is healthy for any barn and business and getting your boarders to do their part will become very easy. After all the winter stuff is gone you will be amazed at how clean an open your barn looks and feels and your clients will feel the same way. It is a great way to start the summer.
I wish you the best in your horse business.