Wildflower and Amaranth Garden - Can I just toss the seed into the grass?

I have big plans for next week, and I'm wondering what you all think.

I have this pretty old house on my property, and I'm thinking it would be a nice location for a patch of wildflowers. I have some mixed wildflower seed a relative gave me (some goofy 'bee and butterfly' variety pack), as well as some lupine and amaranth seed.

I was thinking of planting it all together in this area, on the west and south sides of this building. I rent, so I still have to mow my grass, otherwise it would just be out in the middle of the yard somewhere. This way I can create a perimeter and a 'proper' garden area for it that will be landlord approved.

My plan is to rig up some temporary fencing there at the end of this week when the snow melts off again and put my chickens over there for a few days to till and fertilize it for me. The area facilitates grass really nicely, I think these plants will do well there. I was then going to direct sow those seeds.

My question is, should I just toss the seeds out there and see what happens, or should I mulch in some way to keep the birds off of it? It just so happens we have some cats that like to hang out around that building, so any birds that frequent the area don't last long anyway, but I wonder if I'm tempting fate and the wind to scoop my delicate flower seeds away.

If I mulch, what should I use? Or do I need to be more deliberate about this and mound up some hugelly bits, topsoil, and compost, and create a garden bed for them? Should I add some hairy vetch as well, or do I run the risk of that taking over the space and ousting the other plants?

I have had a lot of luck with just throwing seeds into the grass. Peas, sunflowers, tomatoes, poppies, and tons of other seeds have germinated in the lawn. The time of year and type of grasses will have some bearing on the germination. I hit my entire grass area with a seed mix last winter and here it is, beginning of spring and I'm seeing tones of stuff getting started throughout the grass, and since its Bermuda the grass is still dormant.

Sounds like a plan. I do it in late summer/early autumn. I simply walk around the yard and sprinkle seeds where ever I can see dirt through the grass blades. Then when the seeds start to sprout I maintain the surrounding grass with a weed eater. You'd be amazed how groomed a lawn can look if you just keep sharp edges around the wild flowers and along obstacles like fences and furniture. These pictures are from my yard this morning. The first one is the back yard, which was planted last fall.

The second is the front yard which reseeded from the flowers planted two years ago. You do have to let it get a little ragged looking while the seeds form for these results. A mix of plants with different flowering times might help, but wouldn't give you a dense stand of color.

Oops, here's the front yard